Ideal Assault Rifle

Not sure I understand what you mean. The only components that touch the barrel are the reciever mount, and the gas piston port/block. The piston itself would be somewhat freefloating beside the barrel. This leaves you able to mount whatever sights you want on the top and sides, as well as whatever additional equipment you want underneath. If you will notice the "forgrip" is removable and has a standard rail mount. There IS however a reason to mount something else on the barrel. The LMG version would have a windage and elevation adjustable front sight, which could be calibrated back at the "base". This would allow all the barrels in an LMG unit's inventory to be zeroed before going in the field, keeping the zero somewhat repeatable between barrels. A side benifit would be using the front sight post as a "handle" for removal of the barrel. Another option would be using a scope and rail mounted on a heavy barrel for a modular sniper weapon. You can take the barrel out of the reciever and still keep zero on the scope because the scope is attached directly to the barrel, all of which is freefloating.

Coolhand: You want the rounds to already have a 45 degree angle inside the mag? Have you calculated how many rounds you are able to fill it with?

I believe it would reduce capacity significant. Maybe with more than 50% compared to normal stacking...

Another problem is that such a magazine/feed mechanism will be very complicated, and could be prone to jams, as is the original P90...

However, I like the layout of your drawing, and if you simplify the design a bit, by using the ejection-well as a mag-well instead, and shortening the bolt and the receiver a little bit, and adding an adjustable buttstock, it would match my criteria exactly...

And Solidpoint: I dont know if you have fired any bullpups, as I have not. The closest I«ve been is playing around with an SA80 in Kosovo. I actually liked the layout of the weapon, compared to the G3-rifle, as it had superior ergonomics, and felt a bit lighter.

While being praised for its accuracy, the only complaints with the SA80 that I heard from the Brits was the bad reliability, and the fact that you can«t fire lefthanded.

Other things people tend to complain about bullpups is that the rounds go off right next to your face, and that changing mags is slower than normal.

My design will help a bit with the two last issues, while the two first is up to the internals of the rifle...

This rifle does by the way not "shoot from the armpit", as it will shoot from just over your right hand.

I would have kept the exisiting bullpup layout, except that I was trying to solve the ejection issue. The 45 degree turn actually simplifies the p90 mag design without loosing too much magazine capacity. My guestimate was a mag load of 30 to 40 rounds. If you don't mind having a magazine the width of a standard AR mag mounted flat above the reciever, you COULD do 90 degrees and bump up the capacity to around 50. Also, instead of the "slide in from back" loading method, I am working on a "slide in from side" method that would basically use the incoming magazine to kick out the other magazine during a swap. Your trigger finger would push in a mag release that would depress a latch on that side of the weapon, allowing the magazine to fall out that side as your other hand pushed in the new mag from the opposite side, locking it in place with the same motion.

Oh and the mechanism and trigger pack are straight off a Steyr AUG. I figured use an existing design and then tweek it a little here and there.

http://royalmarines.mine.nu/library/sa80.jpg

It looks like the SA80 fires from about 4-5" behind the hand. I have not fired a bullpup and was hoping to provoke a response from someone who had. I still think there is something to the "unnatural" firing position, even if the back of the barrel is 6 inches from the armpit - but would yield to experience if others who have experience find it equal or better than the conventional layout. To make this point a bit more clear by extension, imagine a rifle with a 50" lenght where the butt was 15" back and the trigger 10" ahead of that so that most of the gun was behind you. This would clearly be an awkward weapon to use. Drawing on another field, dragsters were front engine for decades because the driver is in a much better position to keep the car under control when seated at the very back instead of 10-12 feet forward. My concern may be much to do about nothing. I don't really know. If the concern is legitimate though, having a P90 feed but from the rear instead of from the front is a nice solution with a lot of promise.

BTW, the triangle-shaped foregrip of the SA80, turned upside down, seems about the correct shape for the design I propose.

I see two things wrong with the P90. The weapon is designed to fire from the hand having too short a butt to fire comfortabally, and the top-mounted mag would get in the way of optics, lasers, backup passive sights, etc. I also don't like "curvy" guns. Curvilinear surfaces may look sexy, but they are almost impossible to mount new gear on. IMHO this is why mature systems are always cut down to bare bones with lots of gear "velcro" like rails to mount things on. Curves are there for REMF jerks who buy $70 million fighters because they "look right" - which is of course why NASA invested 25-35 BILLION dollars to create computational fluid dynamics - so some REMF asshole could buy something based on his god-like ability to know how a plane flies by looking at it. :mad:

Stepping off the soap box, the requirement for a weapon to be ambidextrious should not impare at all the function of the gun for the 90% or so right-handers. Not only is this common sense, it is an engineering mandate. One should never design so as to impare the majority use to satisfy a minor exception condition. For an additional $150 - $250 the DOD can just order a special L-handed weapon. This would be one of the smallest of all costs to accomadate left handers and degrading the performance of a weapon system to save such a small amount of money is inexcusabally stupid. I would say IMHO, but this is such a well-established maxim of engineering it should be universally understood by purshasing agents. I am not claiming any particular weapon violates this principal, just that it should always be kept in mind when designing.

Having said this, the FN2000's downward ejection seems unlikely to be acceptable in an AR firing multiple 1,000 s of rounds. Imagine firing into a headwind from a prone position in desert dust, or the pile of shiny brass giving your enemy your exact location during the day, or the casing's heat at night. This seems like a questionable design to me.

Also, instead of the "slide in from back" loading method, I am working on a "slide in from side" method that would basically use the incoming magazine to kick out the other magazine during a swap. Your trigger finger would push in a mag release that would depress a latch on that side of the weapon, allowing the magazine to fall out that side as your other hand pushed in the new mag from the opposite side, locking it in place with the same motion.

Smooth! I like it. http://candlepowerforums.com/vb/images/icons/popcorn.gif

I see two things wrong with the P90. The weapon is designed to fire from the hand having too short a butt to fire comfortabally
Easily fixed on the P90 by adding a sliding/adjustable stock. Also the P90 was designed to fire while wearing body armor which nessecitates a shorter stock
, and the top-mounted mag would get in the way of optics, lasers, backup passive sights, etc. I also don't like "curvy" guns.
Can't change your opinion on the "curvy" guns, but it is really comfortable for one thing, and my "redesign" makes the curvy grip and forgrip modular and removable. They are great for CQB but I can see the redundance with a GL or sniper platform, so you give the guy a rifle that he can stick a different grip on. I was just using those as a base line because it makes the weapon more compact and I was working on the "smallest" package. you can ALWAYS make a gun bigger.

Stepping off the soap box, the requirement for a weapon to be ambidextrious should not impare at all the function of the gun for the 90% or so right-handers. Not only is this common sense, it is an engineering mandate. One should never design so as to impare the majority use to satisfy a minor exception condition. For an additional $150 - $250 the DOD can just order a special L-handed weapon. This would be one of the smallest of all costs to accomadate left handers and degrading the performance of a weapon system to save such a small amount of money is inexcusabally stupid. I would say IMHO, but this is such a well-established maxim of engineering it should be universally understood by purshasing agents. I am not claiming any particular weapon violates this principal, just that it should always be kept in mind when designing.
You are forgetting about CQB where a righty might have to shoot lefty to maintain cover as best he can while shooting around corners.

Having said this, the FN2000's[QUOTE=solidpoint]I think you meant forward, the P90 ejects down while the F2000 ejects forward through a tube

[QUOTE=solidpoint]downward ejection seems unlikely to be acceptable in an AR firing multiple 1,000 s of rounds. Imagine firing into a headwind from a prone position in desert dust, or the pile of shiny brass giving your enemy your exact location during the day, or the casing's heat at night. This seems like a questionable design to me.

Which would be better, a somewhat unobtrusive hot stream of cases dropping out the bottom of the gun, maybe even into a brass catcher, or an arcing stream that shows up like a fountain of brass in thermal and infrared, and not only gives away your position, but possibly showers your compatriots with hot brass? The guys at FN weren't trying to be gimmicky when they came up with the top feed bottom eject
Oh, and belive me, with the built in sight rail and replacing the forgrip with another rail, you get plenty of places to attach gear even on the PDW/CQB version. If I remeber correctly the P90 even features fixed iron sights on the left and right side of the top attachment rail for the eventuality that any optic you mount or it comes with might fail. And since they are perminant, there is no deployment time needed to "flip them up".

I'm not forgettimg about CQB, but it too is a special, low weapon count requirement. I don't want a car engine that gets great gas milage above 130mph - or one that gets great milage below 20mph. I want one that gets great milage at the speeds I spent 99% of my driving at.

Littering the floor with shell casings 1-2 steps ahead of me is NOT what I want when entering a hostile room. It pretty much insures I will fall on my face or ass in 1-2 seconds. If we are collecting the shell cases ANY direction or mechinism will do. Shells ejected 5-8" from the pavement or any other hard surface are not going to dink off my helmet, some significant % are going to spin back at speed right into my face when prone, blinding me and perhaps even do permenant eye damage. They will also quickly pile up and impare the operation of the gun. When flying through the air from conventional designs they have time and airflow to slow down and COOL DOWN. If caught by the wind they will dispurse and in no case will they have the residual energy to injure a comrade observing good procedures. When firing from a bipod over the edge of a trench you will be forced to place the bipod forward and high or have the shells' ejection blocked by the dirt comprising the wall of the trench.

As soon as you put a buttstock on the gun you might as well stop applying fixes for the front feed method and just admit to the superior design of rear feed.

Any clips sticking out at angles from the center mass in the direction of the recoil vector will not only move the gun off target as it fires, but worse still, will change the degree to which this happens as the weight of the shells moves from far off the centerline to nearby the centerline. In short, the arm of the lever gets smaller.

Therefore, I submit that any ideal assault rifle should be fed, to the greatest extent possible, from shells who's mass is right on the line-of-recoil CG. As for ejection, the perfect ejection port might well be forward and up with a snowblower style redirector. Then the tangos have no clue where you are relative to the brass fountain.

I do like the P90 perpendicular feed system, but feeding from the rear seems very clearly superior unless you want esensially zero buttstock. Come to think of it, how about dual feeds so you can always have one nearly full one in the gun. Now I REALLY like the AR concept for the Grendel :D

Coolhand: Another problem with the 45 degree turn is that the mag wont be very much narrower, because the diameter of the casing also comes into play

Internal minimum length of round at 45degrees:

(cos45*L)+(sin45*r)

One possibility could be to attach the mag with the bullets facing inwards, thereby avoiding the width problems, and also the capacity-problem, as the rifle could accept much longer mags than what is used today.

And about the mag-spring problem: Why have a spring in the mag, or a complicated mechanism in the rifle, when the easiest, cheapest and most reliable solution could be to simply use a spring attached to the weapon itself...

And about the quick-swapping of mags:In combat, you dont want to throw away your mags unless you need to. Mags can be refilled, and are seldom empty when changed in QCB...

Front- or back-loading doesnt matter that much, as long as it works well.

Solidpoint: Spent casings on the floor isnt really an issue. Ive been training for FIBUA for a quite long time, and it has never been an issue. When training you always focus on your balance and the way you move.

Also, spent casings arent really shiny, especially since firing in a prone position kicks up a lot of dust...

The only real issue with bullpups is the issue with firing around corners. If you are not in need of accurate fire, the solution could be to tilt the weapon 90 degrees, so the weapon ejects directly up- or down-wards, or to fire it "SAS-style" with a tri-point sling. Not perfect, I know, but a solution...

However, my favorite rifle for the moment must be the HK416, even though the "barre-length"- issue haunts it as it does most "orthodox" carbines. If somebody could make a bullpup as slim and slender as the HK416, while still retaining the forward ejection-system of the F2000, I think they would have a winner! :cool:

If you will look closer at the design, the shells are feeding like the P90 perpendicular design, they are only turned in the magazine at 45 degrees, not 90 like the P90 mag to keep the mag width smaller or close to the overall width of the gun. Actually I need to figure out how wide the mechanism is, and see if turning it a little more like 60 degrees might not work better/allow more ammo in a shorter package.

The reason I prefer the mag forward idea is your magazine length is not limited by your length of pull or your length of pull is not limited by your magazine length. If you will notice, the 30 rd magazine goes right up to the piston/gas block interface. If you try to flip it around aft, you either have to compact the ammo more, or limit yourself to a 20 round magazine…or lengthen your gun, or shorten your barrel to maintain length.

I don't care how far or how much airflow you get on those cases, hot brass stays hot for quite a while. Been there, done that. Even in a high wind, it took more than another mag full during rapid fire for the cases to cool down significantly. I would MUCH rather they were dribbling out right behind my (gloved or ungloved) firing hand and bouncing off my well protected leg and boot to the ground than forcefully ejecting and bouncing god knows where. At least then I know where the pile is. Also, the ejection port on the bottom forces any expelled gasses further away from your face. In a gas tube design this would be a significant amount, but in a piston its not that much. Still, every little bit helps.

BTW, this is for all you M16A2 guys. Almost the same length of pull (planning on an adjustable length pull stock anyway), same sight radius as the M4, same grip,etc. AND its got the GL this time and a full 16.25" barrel.

I know I might be a LITTLE optimistic on the capabilities of the follower and spring, so if anyone has a “formula” for figuring out how much compressed spring goes with how much ammo, it would be helpful.

The length of 5.56 in a magazine, stacked at a given angle:

L=57mm
@45deg=> 43.8mm
@60deg=> 51.8mm

The length of 6.5 Grendel in a magazine, stacked at a given angle:

L=57mm D=11.3mm

@45deg=> 44.3mm
@60deg=> 52.2mm

Length of mag needed per round in single-stack:

Angle________5.56_________6.5 Grendel______Filling-factor

90deg________9.7mm_______11.3mm_________1
60deg________11.2mm______13.0mm_________1.15
45deg________13.7mm______16.0mm_________1.4

Okay, here it is, last change for a while. Kept the pull, grip, and EGL, added the sights off the M4, and the mag is now a 40 rd with a 60 degree to chamber alignment twist done ala the P90. You will notice three "grey" rounds next to the follower. Those are actually follower "dummy" rounds to push the last of the live rounds out. Shortened the barrel just a little more too, just to keep the package nice and tight. Also lengthened the gas system back out to the full length AUG system. Figured as long as I was using it as a base line, I might as well keep the gas system the same too. Can't shorten it down to 500mm like the P90 anymore, but thats only because the trigger pack is so long. I would like to work on redesigning the pack too, but I would have to have one to play with, and the FA packs are restricted and RARE in the US...not to mention AUGs in general.

Oh, I also removed the "Empty space" module behind the ejection port. I designed that to be modular so that you could put a battery pack in it. Ultimately all your electronics would run off that pack, and if it crapped out/got hit, you could just pull a couple of pins and swap out the whole pack, instead of having to keep track of batteries on each piece of hardware.

Cool:

I assume you realize that by angling the magizine you accomplish the same thing as trying to angle the ammo in the clip? It narrows the the top of the gun...and with no reduction in ammo load.

Q: how are we ejecting down and forward with an M203 attached below the action?
:confused:

Um, I guess I wasn't clear. The magazine runs straight along the top of the gun, the ammo inside is 60 degrees off bore axis till it gets above the chamber and then it does the P90 styl turn to get to the feed ramp. Keeps the balance characteristics of the P90 while letting you use an 5.56/6.5G/7.62R sized cartridge.

To load the magazine, one slides the magazine in from the side (if right handed you hold the grip in your right hand while slapping the stick in from the right side of the gun with your left hand, forward end in first, and then the back end second), then when you eject the spent mag, you hit the release lever, and tilt the gun away from you while using your weak hand to push in the new magazine. The magazine ejects from either side, and partial sticks can be retrieved just as easily as partial AR15 mags. You just hit the release, and tilt the gun towards you instead of away, grab the magazine, and then slap in a fresh one.

Its not ejecting forward and down, its ejecting straight down, behind the pistol grip. If you look, directly underneath the bolt, a little behind and below the chamber, is an "empty case" showing where the ejection port is. If it would be clearer, I will add leaders to the drawing. The EGLM (FN's product improved "tilt tube" grenade launcher) is forward of the pistol grip and mounted on a rail (Picitinny) that extends forward of the trigger guard.

... so its ejecting the spent, hot shell casings onto my bare arm right about where the top of my glove ends? This can't be a good thing.

Not quite. Thats why its got a brass chute that directs it down past your arm. The chute is removable for different applications. I'll get the exterior finished and then do a sketch of the sniper, PDW, and LMG versions for comparison. From what I have heard none of the P90 users have ever complained about the brass winding up in a tender spot.

BTW, still tinkering with the internals. Working on a shorter trigger pack

edit: I rewatched the sales vidio I downloaded from Defense Review. Looking at it, the chute under the ejection port keeps it well away from your tender wrist and underforearm. I can see the occasional "shell in clothing" in odd situations, but that happens with ANY rifle. If you want it do eject left/right just replace the chute with one that directs it that direction.

Quick post, since this thread has been quiet for a while. I'm looking at different mechanisms/actions for designing our "Ideal AR" (actually shouldn't it be a Battle rifle? Its got the range requirements). I have pretty much made up my mind for my design, but I would like to get some input from the group on preferred semi/full automatic mechanisms and pros and cons that go with them.
For instance, the AR-15/M-16 direct gas impingement.
Pros: Light weight, fewer parts, no mechanism attachement points on barrel. Cons: Direct gas impingement fouls your mechanism, lots of little nooks and crannies to clean, lots little parts that can get lost or break in the field rendering your rifle inoperative without replacement.

I was about ready to call the Coast Guard as I thought you might have fallen overboard :D

What about a top mounted helical magazine like the ones on the 9mm Calico and Russiaon Bizon SMG? We could to the math and figure out how long a helical magazine would have to be to hold a given number of rounds.

The advantage of helical mags is they would mount on top and eject downwards without requiring a mechanism to turn the round into alignment with the bore axis.

The disadvantage of a helical mag is bulk - there's space in the middle of the helix.

Quick post, since this thread has been quiet for a while. I'm looking at different mechanisms/actions for designing our "Ideal AR" (actually shouldn't it be a Battle rifle? Its got the range requirements). I have pretty much made up my mind for my design, but I would like to get some input from the group on preferred semi/full automatic mechanisms and pros and cons that go with them.
For instance, the AR-15/M-16 direct gas impingement.
Pros: Light weight, fewer parts, no mechanism attachement points on barrel. Cons: Direct gas impingement fouls your mechanism, lots of little nooks and crannies to clean, lots little parts that can get lost or break in the field rendering your rifle inoperative without replacement.

Main pro of the gas piston system is heat transfer. By that, the heat of gas is moved forward of the aluminum receiver rather then vented into it heating it up to high levels especially in full auto fire. If you notice in pictures from the middle east, a number of soliders are wearing nomex flight gloves.

The fouling argument is subjective since the gas and powder fouling is venting into a large area vs a gas system which would have it crammed into a small piston system. Yes, you could go to a low residue powder, but the benefit of such a powder would be realized by either gas system.

Everyone who has ever scraped carbon out of an M14 gas piston, please stand up. It is much much easier to clean the receiver of an AR15 with the open system then having special tools to clean a gas piston.

I dont know what parts get lost,,, the open gas system has only a gas tube and the only clogged gas tube I have ever replaced was from someone sticking a pipe cleaner in it trying to clean it. When you look at a gas piston system, you have a gas tube to get the gas to the piston, the piston, the piston chamber, the seals, vents, spring and an operating rod to push the bolt open. That is a whole lot of parts to take apart and run the risk of loosing.

It is a shame we cant get them anymore, but I always liked the Steyr Aug.

Heh, thanks...been doing a complete redesign of the guts of my rifle design. Cut the ammo capacity back to 30 (but I'm going to design a 50rd hicap to go with it ;) ) for the slimmer profile. I'm keeping the P90 stock configuration, with an adjustable length pull and cheek weld height. I picked a certain action because theoretically I can make its gas piston system almost as small as the P90 straight blow back and still handle the 6.5 G lenght and width cartridge with minimal modification.

My initial design was a modifide AUG, feeding from the top instead of the bottom. Yah, I know the M-14 piston can be a bitch to clean, I have a mini-30, and they arn't much different. I was however looking at simplifying the piston system so that it is either self cleaning, or it is just basically a gas port like the one on an AR15, only instead of jetting it down a tube, it acts on the operating rod. Very similar to the Mini system, and not as complicated as the M-14's system.

I initially considered the Helical, but the spring assembly takes up too much room, creating too bulky a magazine to quickly replace. It also makes them more expensive and complicated...doing field repairs on a P90 mag would be MUCH easier than working on one of those helicals...one of those breaks on you, you might as well just pitch it...too many parts. The P90 mags are basically just a stick mag with a "turn" in the end to rotate the ammo and some follower rounds to push the last of the rounds out of the mag...much simpler. Its the same principle as the follower rounds in a Beta mag.

Thinking about this a little more, I'd be more interested in improving the process by which the latest "ideal assault rifle" gets produced. I'd really like to see the use of the best product and project management practices.

First, you'd want to explicitly state your assumptions. For example, current state of the art metal cased ammo technology, rather than a "metal storm" type solution or G36 caseless solution.

I'd spend a lot more time on requirements definition and prioritization than small arms projects typically have (based on my reading). I'd also try to base the requirements on empirical data. IIRC the Brits did a pretty good job of this with the .280 British and EM2 (but I'm dredging up ancient memories of Small Arms of the World by Ian Hogg).

For example, how much recoil can an average sized soldier with the normal amount of training tolerate and still shoot with the desired level of accurately in semi auto and automatic? That would define one of the requirements--recoil impulse must be less than N.

Another example, would be incapacitation (terminal balistics) with Hague compliant bullets.

You'd need required and desired minimum accuracy requirements.

I'd look at historical and probable future engagements and determine minimum and desired maximum effective ranges.

Systematically building a "wish list" based on empirical data would be the first step. Then, I'd weight the different factors, because I would have to compromise on some of them, and I'd want to compromise on the ones that were least important. Again, the weights would have to be based on real data from historical engagements and probable future engagements.

I like the idea of modularity. That would permit you to adapt the general issue weapon for specialist use (e.g. PDW, designated marksman, or LMG).

It would be even better if you could design a whole small arms suite at the same time--A handgun/PDW and ammo for use to 25 or 50 meters, an Assault Rifle and ammo (also adaptable for designated marksman or LMJ roles) for use to say 500 meters (or more with a longer barrel in the designated marksman or LMG roles) and a heavy sniper/machine gun round for use against armored targets. material or targets beyond 500 meters.

Thats basically what I have been doing...or trying to do. I have my preferences, other people have thiers, I'm just trying for what I belive is ithe best.

BTW, the G36 is a 5.56 piston based AR, basically the european version of the XM8. I believe you are thinking of the G11 which was a 4.7mm caseless design (strangely enough I've been looking into the design for some mechanical inspiration recently). The Metal Storm in my opinion would be good for a GL barral on an OICW (or AICW as the Aussies call it...God Bless them), but not for the assault rifle.
Note on the .280 brit and the EM2. Good concept, slightly anemic round. The Grendel does it better ;). The EM2 itself only had one flaw that I saw. Righty only (typical Bullpup problem).

Current state of the art cased technology: Not much new under the sun there, other than a PDF I ran across for a telescopic cased round for a next generation SAW. The concept was not unlike that of the G11 chamber/cartridge concept, except that the chamber swung out sideways to allow the new round to be pushed in while the previous round is pushed forward and out of the firearm (love the idea, but it requires a cylindrical case with no necking or "rim" on the case head). They designed the weapon so that it would be easy to convert from the cased telescopic to the caseless ammo with something on the order of 80% commonality between weapons.

Recoil: More than a 5.56, less than a 7.62 NATO :D

Desired minimum accuracy: 2 to 3 MOA for most PDW to AR applications, 1 MOA if at all possible (or less?) out to 500 to 1000 yards depending on barrel length
(Why 1 MOA? cause I like the EOTech sight and that would put all my bullets in that little red dot at whatever range I zeroed it for.)

Maximum effective range (desired): Horizon? :p
Realisitcally (as far as I can identify my target)

I'm currently working on the exterior views (simplified) for what I am calling the Elliott Armament model One or the EA-1. I'm going to do side view of PDW, CAR (M4), AR (With or without GL), SAW, and DMR with a scaled pic of a comparable well known rifle next to it. Why am I not doing a view of the guts? Cause I am still working out the details and if it sufficiantly different from existing designs, I might want to patent it! :eek: Who knows...might have to go get that degree in mechanical engineering so I have the credentials to start my own gun company.

BTW, the G36 is a 5.56 piston based AR

D'oh! I can't believe I typed that! I meant G11. I've read a lot about both.

Back to modularity--Have you seen MGI Military's Modular Lower With Interchangeable Magazine Wells (http://www.mgimilitary.com/Lower_Receiver_Mult_Mag_Wells.htm) and Quick Change Barrel (QCB) Upper (http://www.mgimilitary.com/qcb.htm)? That combo makes for a pretty flexible AR based system. They could build on the system further by offering a "short action" mag well and upper for .308 based rounds and piston-based upper options.

Something like the MGI system is intuitively attractive. Among other things, it permits you to use your adversary's ammo. I know there have been times when our troops have wanted that in Afghanistan and I read the british were able to sustain offensives in the Falklands when their ammo ran low by picking up Argentine ammo.

I think MGI's CQB upper and modular lower would make switching from 6.5 Grendel (IF we adopted it) to 7.62x39 (and 5.45x39 I think) a snap! Just switch the barrel and magazine well.

The MGI stuff isn't really "ideal" but it's a nice evolution of the AR system.

Another idea I've kicked around while thinking about the ideal assault rifle is the ideal optical sight. A periscopic optic would permit a raised eyepiece and "straight line" layout like the AR's while minimizing the effects of canting on a raised (2.6" on the M16) sight line by putting the line of sight closer to the bore. You could mount a backup aperture on top of the eyepiece and use a flip-up front backup sight. Thoughts?

Maybe it's a solution looking for a problem. The AR's high sight line has never caused problems for me.

Actually the 5.45 is a narrower case and smaller case head so that wouldn't work, but I have been kicking around the idea for the 7.62x39 American for a while. Basically its a grendel case necked out to 7.62. You would have higher case capacity (and a few other perks like Gren performance with a saboted 6.5mm load) but also be able to use the 7.62x39 russian, which would fire form in the chamber. They couldn't use our ammo, but we could use thiers.

As for "quick change barrel" issues, I've already incorporated it in the design, in fact I kinda sketched out a 11x39 round for use in CQB. Think .45 winmag to .44 auto mag or better...or a slightly narrower Beowulf. And all it would take is a change of the barrel and gas piston port (part of the barrel assembly) and swapping mags. Neat eh :D

To follow up on Essayons mention of the MGI Quick-Change-Barrel upper and modular magwell lower receiver, I can post a few things as the MGI factory rep.

This MGI QCB system employs a cam-lock for the barrel extension which is operated by a pair of levers under the handguard. The barrel change can be accomplished in under 30 seconds, and the gas tube remains on the barrel assembly when changing barrels. Normal AR15 barrels are used, without the barrel nut, or delta ring, or handguard keeper on them. No special proprietary barrels needed. The return-to-zero, and repeatability of this system is exemplary. Capable of sniper grade accuracy. It has been on the market for 2 years now, and has shown excellent reliability and wear characteristics.

The upcoming MGI Modular Lower Receiver(available in a few weeks) has an interchangeable magwell system which will initially come with an AR magwell and an AK47 magwell. Other magwells will follow later. To use AK mags, the upper must be relieved internally to allow the AK mag to seat as high as is needed for correct operation, and the MGI QCB is now coming standard with these relief cuts, to work with the MGI Modular Lower Receiver.

I use the ABS carbon fiber barrels with my MGI package for best performance and light weight in the system. ABS is negotiating at this time to be licensed to produce carbon fiber barrels in 6.5 Grendel by AA. The Grendel mags will work in the AR magwell.

By changing the barrel, bolt, and magwell/mag, almost any caliber that will fit in the AR platform can be used. Using currently available AK mags in the AR will be a boon to 7.62x39 users, because no more frankenmags will be needed, and your hi-cap AK mags will go right into our AK magwell.

This is the most modular system ever made for the AR family. Upcoming magwell options will include pistol calibers too, such as 9mm and 45ACP, and also rimfire calibers.

MGI has also requested license from AA to sell barrel, bolt, and mag packages made by AA for 6.5 Grendel caliber change packages that would be sold for an MGI QCB system. I don't know if this will be granted, but we have asked for it.

As Essayons mentioned, it is possible now to extrapolate this system to use with an AR10-type upper for use with longer cartridges with a longer magwell on this modular AR15 lower, but we do not have that available at this time.

The belt-feed module will be coming along shortly for this lower. This option, along with our drop-in OpenBolt Full-Auto/ClosedBolt Semi-Auto fire control group will allow SAW option configurable from the duty rifle. Switch back to a normal magwell and long barrel, and you have a precision/sniper platform. Switch to a short suppressed barrel and a pistol magwell, and you have an SMG.

it is possible now to extrapolate this system to use with an AR10-type upper for use with longer cartridges with a longer magwell on this modular AR15 lower, but we do not have that available at this time. The belt-feed module will be coming along shortly for this lower.

When will we see the .50 BMG mag well and upper? ;)

By the way, MGI is doing some cool stuff but I am not affiliated with them in any way (I'm a Washington CPA and AR enthusiast who recently became interested in 6.5 Grendel). I know I'm always suspicious of a web marketing blitz when newbie posts about something are followed up by manufacturer or vendor posts. I posted links to ABS's and MGI's stuff right before TWL showed up, but in this case, TWL is just on the ball.

http://www.photomosaic.com/gns/mgi.jpg ... QCB option pic...

:D The MGI system is almost the embodiment of the AR dobrodan and I were discussing for the Grendel - with the addition of an optional belt feed. My observation is that after 9/11 private industry first filled the easy holes by making fantastic rucks and accessories - then came excellent body armor, and finally, because of complexity and expense they have gotten around to creating some absolutely awesome small arms weapons.

I am just amazed at what American ingenuity has been able to accomplish, swimming upstream against the fat, slow, bloated, territorial mega defense contractors who stifle competition and innovation in every possible way every single day. I hear this same complaint universally from small companies I have worked with on the PAV project. The consolidation of the arms industry, subsidized by the Clinton administration, has led almost without fail to the most expensive possible way to solve any military problem, because only these big-ticket items will sustain the billion dollar cash flows these rancid companies need to survive.

My hat is off to all of the industrious and innovative souls out there that are pushing the state of the art FAR beyond what the military even believes is possible. I believe it has been within the last 2 years that the DOD concluded there were no more worthwhile advances left in the small arms arena. This reminds me of the idiot who wanted to close the patent office in the late 1800s because "everything worth inventing has already been invented" :eek:

Wait till you see the MGI Modular Lower!
This is a photo of a recent prototype.
Of course, the production models will be better finished.
AR and AK magwells shown.

http://photos.ar15.com/WS_Content/ImageGallery/Attachments/DownloadAttach.asp?sAccountUnq=53166&iGalleryUnq=1956&iImageUnq=39497


Unique buttstock is a prototype solar-powered battery-charging buttstock, with the ability to passively charge batteries during daytime operations, and also can double as a Claymore detonator, obviating the need for a "clacker".
No plans to release the buttstock as of yet, but we're working on a full electrical distribution system for all electronic items on the gun.

What about a kinetic-energy charger, like you have in some flashlights... A bit less high-tech, but will work all over the world, even at night, which means 6 months at certain places...

If youre running out of power, just shake your gun...

About carbon-fiber-barrels, I believe they would be great for sniper-weapons, as they dont tend to get very hot. But for an assault/automatic rifle, I believe the barrel wont handle the heat well. This is because while carbon fiber is a better heat-conductor than steel, it probably has less thermal-capacity than steel, and given that the surfaces of the steel barrel and the carbon-fiber barrel are of the same size, approximately the same amount of heat will be transferred to air from each barrel at the same temperature.

Because of the lower thermal capacity, the carbon-fiber barrel will get hot faster than steel, and will also reach a higher temperature faster when subjected to continous automatic fire.

I dont know the "safe" max temperature for a carbon-fiber shrouded barrel, compared to a steel-barrel, but I would have been surprised if the carbon barrel could handle higher temperatures.

There are ways to increase the the heat-transfer to air, and one of them is to increase the surface of the barrel in contact with air, by using a fluted barrel. This could work for the carbonfiber barrel as well, but it would still get extremely hot very quick.

I believe a good solution could be to make a ceramics/carbonfiber-enshrouded barrel if possible, as that would make sure the resin doesnt react with the heat, and increase the thermal capacity while still being a good heat-conductor, and retaining a high strength even at extremely high temperatures.

Please correct me if needed, as Ive not done any research in this field...

Kinetic energy charger is definitely an option, but does require some kind of motion, which may or may not be present, or in the direction needed to move the system. It can work, though, and could be even more viable as a hybrid system along with the solar. I chose solar because it is independent of movement, and the sun will be fairly predictable to be available much of the time. Also, it was very lightweight and low bulk with this package. No magnetic charger could have been this lightweight and low bulk.

Regarding the carbon fiber barrels, it is the speed of conductivity that makes the difference with the carbon fiber system we use. It is high thermal conductivity with very low mass, and thus low thermal storage. The temperatures move quickly from the barrel steel to the air inside the handguards, and uses the large diameter barrel(HBAR diameter) for a good amount of surface area exposed to the air.

With this system, the heat is removed rapidly, from the very beginning of the heat cycle, and as a result, the barrel never gets as hot as steel would.
Tests have been done on ABS barrels with full-auto continuous firing(pausing only to change 30rd mags quickly) that have reached 600 rounds fired without causing cook-offs. In similar military tests, steel barrels had catastrophic failures of bursting at round counts lower than 600 rounds fired.
The outer portion of the barrel does get quite hot, but cools off rapidly. This is the thermal conductivity process in action.

Additionally, in long term testing, the unlined SS ABS carbon fiber barrel suffered 65% less throat erosion over a 10k round erosion test, than a military steel barrel with chrome lining. This is a result of less heat exacerbation of throat erosion, because of the thermal management in the ABS barrel design.

Independent lab testing at Univ. of Nebraska Engineering Dept. showed a 372% improvement in cooling with the ABS carbon fiber barrel system, compared to a steel barrel subjected to the same conditions. The carbon fiber microtubes present in our matrix, made of ThermalGraph DKD pitch-based carbon with a thermal conductivity rating of about 750W/mK is responsible for this thermal performance. Silver(about 402W/mK) has a rating about half that amount, and aluminum(about 270W/mK) has about one third that amount of thermal conductivity. As you can see, this material is far better at thermal conductivity than any metal material, and is only second to pure crystalline diamond for performance in this area.

As it turns out, this system provides the stiffness and rigidity of the HBAR steel barrels, far better thermal performance, and much less weight than any comparably sized steel barrel. It is just as good or better for assault rifle or machine gun use, as it is for sniper barrels. In fact, we have made barrel sets for GE mini-guns that have up to 8000 rounds per minute firing rate. They work great.

This ABS carbon fiber system is different than other previously tried methods of making carbon fiber barrels, and is superior, and patented. It is more expensive than a normal steel barrel, but we have tried to keep the price in the somewhat affordable range, and they are generally under $700 to buy, and we have some as low as $450.

We use Mike Rock barrel blanks as a basis for our barrels, which are very highly regarded for their accuracy performance and quality of manufacture.

I have the unique position of being the factory rep for both ABS barrels and MGI military products.

Happy to discuss any further issues.

Please consider using a slow-moving axial fan to cool the barrel if using a kinetic ( such as a linear motor/generator to control recoil and make electricity ) or solar power source included with the weapon. Even a slow moving ultra-lightweight carbon or metal axial fan should offer 5-10 times the heat dissipation of ambient air alone. (If you want the supporting research let me know and I will be happy to provide you with it.) With good interrupted cooling fins this factor could be as high as 30-100 times depending on the temperature gradient. I am assuming fins would be difficult to do and still keep the barrel from moving around when it heats, but even with a smooth carbon outer, 5x should allow an M240 chambered in Grendel to fire the entire 30,000 rounds of the barrel's life in one long continuous "burst". This would give the USMC, for example, capabilities exceeding that of a 100+ pound water-cooled MG in a package that weights 23 lbs.

(The much lower recoil of the Grendel vs 7.62x51 means the bipod will stand in for the current M240’s very heavy tripod with no loss in accuracy in many situations, further reducing the weapon’s system weight, along with a lighter weapon and greatly reduced ammo load vs the 7.62x51)

A simple axial test fan rigged with a 110 volt test motor - and a lot of ammo - should make for a quick, simple, easy test of the threshold at which there is sufficient air cooling to allow for non-stop(until ammo exhaustion or trigger finger exhaustion) firing of a Grendel based MG. Based on my research, endorsed by some back of a napkin work by Arne, I calculated that as little as a 2x factor in cooling would yield a 100% duty ROF for an M240 in Grendel. This would be a true revolution in firepower!

Btw, having done a lot of research into CF barrels, I think I know exactly what the ABS technology is. There is a certain type of carbon that is a super-conductor and will conduct heat something like 10,000 times as well as silver. Unfortunately, it has few other useful properties. It appears to me that ABS is "doping" their resin with this kind of carbon to conduct heat. If so this is truely a fabulous leap forward in technology and I am very impressed that you've pulled it off!

PS: The Aussies have come up with an interesting assault rifle with a MetalStorm 40mm grenade launcher on top and a rifle (we'd hope a Grendel 6.5 of course) below. The MetalStorm 40mm grenades use electronic primers so they should be especially interested in your electric buttstock. This arrangement allows the triggers to be colocated so only one trigger is needed for both the rifle and 40mm. It has a lot going for it and an ABS barrel would put it in a league of its own.

Ok!

Then I stand corrected! And impressed!

This barrel would be a perfect companion for an automatic rifle, enabling high ROF, and no need for open-bolt firing to avoid cook-offs.

Is it possible to flute this barrel to further increase the rate of heat-transfer to air?

I read in the "superlight" thread, that you have a Electroless Nickel and Silicon Carbide lining, which can increase muzzle velocity by 75fps. If you are able to combine this lining with a polygonal barrel, even higher muzzle velocities could be the tesult. I know HK claims that their 12.5" polygonal barrels gives the same muzzle velocity as a normal 14.5" M-4 barrel.

I'm definitely on the same page with you regarding the air flow improvements around the barrel surface. We have measured and noted the necessary air movement volume that needs to be circulated around the barrel for optimum cooling. MGI has some very interesting prototype systems which are designed for this purpose of moving air, but are relatively lightweight, and require no electrical power. They are under development and testing as we speak, and we expect to need them for the upcoming belt-feed module that is an option on our MGI Modular magwell lower receiver. This protytype is designed to move enough air that will prevent the barrel from ever overheating to a detrimental temperature. Of course, it will be included with the ability to be quickly removed via our QCB quick-change-barrel system, along with the barrel that it is attached to.

This will give our new modular rifle the capacity to be a true LMG/SAW at under 9 pounds, plus ammo. With the Open-Bolt Full-Auto/Closed-Bolt Semi-Auto fire control group we have, it will be able to serve in normal precision operation in closed-bolt selector position, and with a click of the selector it will automatically be in Open Bolt fire control for LMG use. The function is passive to the user, and all he has to do is select which mode of fire on the selector, and the open-bolt or closed bolt operation is automatically put into action. No re-learning of how to operate the gun, just use it as you do now, and the selection of the FCG is done for you when you select semi or full. It drops into existing M16 receivers with no mods to the receiver, and is replaced as easily and any normal FCG. This way, no matter what configuration you use with the modular system, you can use it without being hindered by having to change out the FCG, which would be cumbersome. You can go from duty, to sniper, to SMG, to belt-fed air-cooled LMG in a very short time, all on the same upper and lower receiver and FCG, with just barrel change, possibly bolt change(depending on caliber used), and magwell/mag change, or plug on the belt feed module.

Regarding the ABS barrels, yes we do "dope" the resin matrix with the ThermalGraph DKD pitch-based microtubes, which are designed for that exact purpose. It allows us to use application-specific carbon fibers on the CNC winding tow in an engineered helical winding pattern for maximizing the strength, rigidity, and harmonics control of the barrel, while using another application-specific carbon material in the resin matrix for thermal management.

The cool part about all this is that it is not just an imaginary exercise. It is reall stuff that is happening now, and some is currently available, some is coming in a few weeks, and other parts are prototyped and will be available early next year. We will be entering in the next military small arms competition(like SCAR) with this system.

Ok!

Then I stand corrected! And impressed!

This barrel would be a perfect companion for an automatic rifle, enabling high ROF, and no need for open-bolt firing to avoid cook-offs.

Is it possible to flute this barrel to further increase the rate of heat-transfer to air?

I read in the "superlight" thread, that you have a Electroless Nickel and Silicon Carbide lining, which can increase muzzle velocity by 75fps. If you are able to combine this lining with a polygonal barrel, even higher muzzle velocities could be the tesult. I know HK claims that their 12.5" polygonal barrels gives the same muzzle velocity as a normal 14.5" M-4 barrel.

Not practical to flute the barrel, or otherwise change the surface shape, due to the way the carbon fibers are applied on the winding pattern. Heat transfer can be improved by air circulation over the barrel. In practice, an entire 210 round military ammo load can be fired rapidly by the operator with no effect on the barrel, and even another 210 round ammo load could then immediately follow that one without problems. And even another 210 rounds after that. So it is doubtful that an operator would ever see any concern about barrel overheating problems even in heavy battle use.

For LMG use with a belt feed, then we have some needs for further cooling, and that is being addressed by MGI as I explained in the post above to Solidpoint.

Regarding the velocity improvement with our ElNi/SiC barrel lining material, and/or polygon barrels, yes we have experimented with PacNor Polygon rifled barrels. We have found that the polygon rifle barrels did not provide any significant velocity increase over the normal Mike Rock barrels. Perhaps this is because the Rock 5R rifling already provides the similar effect/benefit of the polygon rifling by giving better gas seal and less bullet deformation. In any case, our testing showed little or no benefit to velocity by a polygon barrel, lined or unlined, over our Mike Rock barrels. However, we do apply our process to PacNor polygon barrels, and we have done a number of them for custom barrel jobs. The PacNor barrels are real good, and if somebody wants to use them with our carbon fiber application on them, we will make the barrel using a PacNor polygon blank. I just wouldn't be expecting to give any noticeable velocity boost over the Rock barrel.

In our admittedly limited testing, we are getting similar performance from our lined 11.5" barrels, that one might expect from a normal 14.5" barrel. If you want to "split hairs" our 11.5" lined barrel would be just a "hair" slower than a normal 14.5", but effectively they would have the same frag range in 5.56. We do not guarantee this velocity increase. Our test sample is too low to go out on a limb with guarantees of this. However, all of the test barrels and production barrels produced so far with this material have shown the increase. It is quite predictable, and after a year or more of results coming in confirming it, then we may start use it for a marketing tool.

TWL, I dont know if you have read my thread on "6.5 light machinegun".
As an old machinegunner myself, I feel that beltfeds are getting too much attention, while magfeds are being written off as next to nonsense.

The biggest flaw of magfeds has traditionally been the fact that you need to change mags very often to be able to deliver a significant volume of fire. This is because the overall size of the magazine should not be too large, to be practical in use. Also with a traditional bottomfed position of mounting the mag, the length of the mag may interfere with the ground in the prone position. With a topfed, you avoid this, and can employ magazines of maximum practical size.
Also changing mags on a topfed in the prone position should be a lot faster than on a bottomfed gun. Especially if you have a co-gunner.

If your carbon fiber barrel is as good as you claim, a top-fed automatic-rifle equipped with this barrel should be able to compete with a GPMG or a SAW, while being much lighter, cheaper and more reliable because of its simpler construction, thereby enabling more of them to be fielded in a squad at the same time.

I feel myself that while I love beltfeds, they are best for mounting on tripods and vehicles, and then preferably in a relatively large calibre.

TWL:
I have many times posted the research done at FSU on the creation of a lightweight 81mm mortar tube - in the last week on one of the threads we have been sharing IIRC.
http://etd.lib.fsu.edu/theses/submitted/etd-09172003-225551/unrestricted/sasi_thesis.pdf

This 96 page document reached the following conclusions...

7.2 Conclusions
A lightweight composite mortar barrel was designed and analyzed. This new design
of the composite mortar barrel weighs 11.68 lbs and provides a potential weight
reduction of 57% when compared to the weight of the current all steel mortar barrel
(27.4 lbs). The lightweight composite mortar barrel allows the soldiers to carry the
mortar with less effort, while meeting the vision of the FCS mission.

Of particular interest should be that 2.35lbs of the remaining 11.68lbs of weight went into an insulating blanket to shield the CF wrap from excessive heat. The ABS process could dispense with this weight and yield an 81mm mortar tube weighing in at an astounding 9 lbs 5oz. This is almost exactly 1/3rd of the weight of the existing system. Applied to the M224 60mm mortar this would imply a cannon weight under 5 lbs. http://www.inetres.com/gp/military/infantry/mortar/M224.html This means every squad could carry several tubes with them even at high altitudes like in Afghanistan and make use of cached or air-dropped ammunition.

More importantly, Zipperhead and several others here have speculated that using the same approach as the SPIKE missile did to cheapen the Javelin - replace the cryogenically coolded IR seeker with a simple visible light camera system - the Bofors Strix sensor-fused (armor seeking) mortar munitions could be make cheaply enought (SPIKE @ $4,000 Javelin @ $100k-ish) to make single warhead mortar munitions practical for the 81mm size. Currently the Strix system uses three warheads in a 120mm footprint, but my guess is this is to get the price up to the point they can make some really obscene profits on it. It can just as well be applied to a single warhead 81mm daylight munition where the muzzle flash will not be seen for tens of miles when fired in daylight.

So... if you can use the ABS technology to enable a squad of SEALS or SOCOM deep penetrators to walk in a sensor-fused mortar munition (ammo air-dropped by a Predator drone perhaps), while providing 81mm mortar protection in the usual mode 100% of the time, you will have given them a huge increase in the ability to seek out and destroy enemy air defense and theater ballistic missiles. (TBMs Ie: Scud missiles) AND give them an awesome ability to counterbattery fire against heavy artillery that may be actively engaging them from miles away. (IMI has 60mm mortars with 8km+ range so 13-15km should be possible with an 81mm) Of course using a PAV they could carry a half dozen tubes ( the base feature is not needed as this feature is moulded into the PAV's structure ) and all the ammo they need to rain down 6x33 rounds per minute per PAV. Assuming 4 PAVs per 12 man squad this is over 750 mortar bombs per minute per squad!!! http://www.inetres.com/gp/military/infantry/mortar/M252.html

The M224 sells for around $15-20k, and the M252 is $25k+, so there is some money to be made here. :D

Dobrodan,
I agree that a top-fed magazine has some benefits, not the least of which is keeping the gun lower to the ground. However, we are working with a modular platform that seeks to keep the basic AR15 layout, while providing more optional configurations.

Regarding being able to field more weapons with top-fed magazine operation, we are offering the capacity to configure any/all duty(with our modular system) weapons into LMG format with the additional carry weight of only a small module which quickly replaces the magazine well, and the necessary belted ammo. Probably also a bipod. In this manner, we believe it would be even easier and lighter to field the weapons in whatever configuration desired, while also providing field-capable re-configuration for whatever the mission requires, with the least number of pieces, and the lowest carry weight possible.

Solidpoint,
Yes, it would seem that using the ABS carbon fiber process on these mortar tubes you describe would yield even lighter weight than they presently envision.

I expect that this technology will see wider use in the near future.

While I have not discussed this particular mortar tube item with my Navy contact person, Commander of US Navy Strike Force Training Atlantic, I do have other items going to him for T&E and we'll see how well they like what they see, and we can expand later.

TWL:

You might contact RobArms as they sell a Bren configuration expedition rifle and would likely be interested in your barrels at a minimum.

http://www.65grendel.com/forum/printthread.php?t=177

http://www.robarm.com/mainpage.htm


PS: Keep me posted on the CF mortar reception. I use it a lot in my book and you have already made me rewrite 3 chapters with the rifle barrels.... :D

I can check with Rob Arms about it.
I'm a bit reluctant to do something with them right now, considering that they will also be fielding a SCAR rifle(or whatever the next competition is called), which will be a direct competitor to MGI.

Maybe after MGI wins the next small arms competition( :D), we can think about supplying competitors. ABS and MGI are not connected, other than by me. But I know all the principles well, and we work together alot, and support each other in our efforts. So, I'm not real anxious to be sending ABS barrels to have them come back and hit us in the face at the next competition.

I will post any info that I'm allowed to talk about, regarding anything that we might do relating to a new mortar tube project, if that ever gets underway.


That's cool that you are writing a book!
Hope I didn't cause you any excessive extra work!

Well, if you are sticking with the AR platform, then yes, the quick change barrel/gas tube upper and quick change mag well lower would be excellent. I'm just trying to work outside the box here. Heck, the MGI uppwer and lower with the quick change barrel and mag well system only has one major flaw as I see it. Ljungman direct gas impingment action. Figure out a way to change it to a POF style gas piston and it would be perfect in my opinion...for a conventionally layed out rifle.

I still like the concept of a top loading/bottom ejecting bullpup...gives you the shortest package with the longest barrel...and if you design it right, you can make it compatable with existing magazines, mag wells, and "saddle drums" like a modified Beta-C

The ABS barrel would fix two of the problems with the MG3/MG-42. Weight and excessive barrel heating and wear.

Given the new slicker barrels, I wonder if the bullpup is worth it? I just don't like things exploding 2 inches from my ear. Maybe for special CQB usage it is, so as a specialized weapon, perhaps. As a standard issue item I'm liking the bullpup less and less. There are certainly many others who's opinions on this matter are better informed, but personally its beginning to look like much ado about nothing - or damned little.

PS: I've tossed this around in my head all night, and have pretty much convinced myself that having 4x heat conductivity, assuming the same or better increase in surface dissipation, would be exactly equal to 1/4th the ROF in terms of barrel wear and heat buildup. This would bring the MG-42's ABS barrel adjusted ROF fire down from 1,200 to 300 rpm!

First of all, I have fired bullpups...not very good ones either (mini-30 in a Muzzlite stock, piece of crap) and the report is no worse, nor were there any problems with the action being under my cheek. Also, if you look at the inverted bullpup like the P90, it puts the magazine in the way of any failure of the mechanism hurting you.

I would also like to point out that one of the most seasoned militaries, as well as one of the most pragmatic and likely to want to minimize troop losses (because they have so few to start with) was or is switching to a bullpup. I am of course speaking of the IDF and the TAR-21 or "Tavor" AR. If they were worried about mechanical failure, they wouldn't have even considered it.

Don't get me wrong, I see your argument. My return argument is, a properly designed rifle would aim any explosive failure of a rifle away from the rifleman. Put a ceramic plate over the action and under the cheek weld and call it good if you are that worried about a mechanical failure of your weapon. Gasses are vented down, cases are ejected down, and frankly, even with those crappy muzzlite stocks, you don't percive any real lack of saftey and those eject right next to your face. Put quite a few magazines though mine till I gave up on it (mechanical failure of a different kind relating to the recoil causing the takedown lever to disengage)

Theres my argument..sorry if I sound like a broken record.

[QUOTE=Coolhand77]Heck, the MGI uppwer and lower with the quick change barrel and mag well system only has one major flaw as I see it. Ljungman direct gas impingment action. Figure out a way to change it to a POF style gas piston and it would be perfect in my opinion...for a conventionally layed out rifle.
/QUOTE]

Thanks for your complimentary comments about the MGI package!

Regarding the direct gas impingment system vs "non-inline gas piston operation", we have some views about that too.

First, let me say that the designer of this system is Mack Gwinn, who was the original founder and owner of Bushmaster Firearms(since sold it), a partner in Armforte Inc(partnered with Jim Sullivan of AR15 rifle-design fame), designer of MWG scope mounts and magazines, and owner and designer of all MGI products now offered. He's an Army Special Forces vet, and has been designing firearms since 1976 for the military and commercial markets.

Now, since Mack has been doing this stuff for awhile(30 years), he has designed and built military and commercial rifles and pistols with gas piston designs on AR15-based or similar lowers, as well as others. In fact, Mack's first commercial design(30 years ago) was basically a variation of the AR15 lower, with a piston operated top end on it. You see, this idea that adding a piston system to the AR15 would result in the "ultimate system" is not new. It is very common for people to look at the AK47 and note that it works in nearly any conditions, and to think that if we could just put something like that on an AR, it would be great. But the AK's adverse conditons reliability is more related to the loose operating clearances.

However, after years of working with various designs like this, it was found that the piston operating systems that are over the barrel(or under) have problems of their own. And it is our opinion formed over the years, that the problems that occur with these off-axis piston operation systems outweigh their benefits. We prefer the direct impingement system now present in the AR15, and we feel it is superior to any off-axis piston system, no matter who makes it. (Personally, I think the POF is a fine system.)

Of course, this probably comes as a shock to some, because of all the hype lately about piston operating systems. But, since we are weapons designers, this hype doesn't have much effect on us, as we already know the pros and cons of such systems.
Pros: Weapon can run cleaner in the breech area.
Less heat in the bolt/carrier group.
Cons: Barrel is no longer free floated.
Additional harmonic vibrations introduced to the barrel by piston motion.
Movement imparted to the barrel by overhead system being non-axial.
Non-axial masses present, and now getting into reciprocating motion.
Non-axial force vectors now present at carrier key/carrier.
More weight.
More parts and complexity.
More expense.
High heat generated into handguard area, and around barrel.
Increased recoil and muzzle flip from moving masses above the barrel.

Now, of course I realize that some piston system makers(which shall remain nameless) deny all of this vociferously, because if people actually knew that direct gas impingment has very little wrong with it, that there would be no need to purchase very expensive piston operated uppers from them(which solve only one or two issues, and generate many more of their own).

The simple fact is, that while the AR impingement system appears to run dirty(and it does), this does not interfere with its reliable operation in active duty. Regular AR15 rifles can(and do) run thousands of rounds regularly without cleaning, and still work just peachy. If you want to bring the Iraqi sand/dust into the discussion, NOTHING runs for long over there, and that includes AK's, AR's, piston operated systems, and anything else.

So, as a long winded way of saying it, we are not "chasing the piston design" like other people are, because we prefer the reliable simplicity, and the high accuracy performance potential of the existing AR impingement system.

This does not mean that we don't have piston system designs up our sleeve. If it comes to pass that the military markets and commercial markets are more interested in faster cleaning, than they are in shooting performance, then we will respond to market demand and produce some of our piston designs.

Right now, we are ready to put up our design against anyone in the world, and we will be doing just that in the next advanced combat weapon trials. Because the gas operating system is only one part of the weapon, and there is alot more to a combat weapon than "cleaning time". :)

Regarding bullpup rifles, I've owned a few, and think they are pretty cool.

But they have their own issues to contend with, and not everybody is happy with them.

It's basically a trade off of the advantages of having the longer barrel in a shorter overall length of the weapon, vs the poorer ergonomics, balance, and handling. And some designs have flaws which limit shooting on only one side of the gun.

There's nothing wrong with using them, if they meet a need and you can accept the drawbacks.

TWL:

IIRC current mortars operate in the 15k psi range, much lower than 60k psi for rifles. I believe this is because the mortar has always been used as a more organic fire-support weapon than field artillery. If one used current metal technology and increased pressures to the level of artillery pieces they would of course weight as much as arty.

One idea worth exploring with your Navy contact would be to offer a 60mm or 81mm barrel that is perhaps 20 calibers long instead of 15, and with 2-3x the strength implying a mortar that weights 50-60% of current units instead of 30-35%.

There are two main arguments for this approach. The first is that it would allow a much lighter 81mm system to do most of what the 120mm system is currently doing which would allow the FCS systems like the Stryker to cut perhaps 1-2,000 lbs off the vehicle weight. I cannot reveal my sources, but the Army is now taking some extraordinary measures to get the weight of the Strykers down because deprived of practical C-130 airlift they lose the element of surprise in any large land operation.

The 2nd argument is that it allows infantry in mountainous areas, or with other terrain features that offer reverse slope tactics, to "maneuver in place" and provide mutual support to each other's positions.

It is an old truism that where arty is concerned range can be substituted for maneuver WITHOUT having to limber and unlimber, break cover, drag along ammo and logistical support, be exposed to interdiction or other enroute engagements, etc. It also means that many fewer tubes can effectively support each other's positions because their fields of fire are overlapping. As and example; imagine you are in mountainous terrain where the ridges are spaced 10-12km apart. With current technology only 120mm mortars could support each other's reverse slope positions from behind the next ridge (Operation Anaconda). If the range of 60mm & 81mm mortars could be increased to 12-18km - as should be practical using ABS technology, not only could positions in the same geometric plane support each other, but others offset to the sides for miles could also support a position in danger of being overrun.

This would require 60mm mortars with 5-7 charge doughnuts instead of the max of 3 now, but with a lower total launch system weight and much lighter munition weight than the 120mm or even 81mm (4, 15, 21 lbs respectively IIRC) more tubes and more rounds could be carried on foot or by small vehicles such as the Prowler RTV. These "Magnum" mortars could of course fire all existing ammo, but with the added length/heat dissipation area, and ABS cooling, at a pratically unlimited ROF ( 33 RPM x 4-5 forever ) AND some additional range due to the extra barrel length.

If you Google around you will find some very good tactical pilotage maps of the Sufed Kot range from Jalalabad down through Khowst, Orgun and almost all the way to the Baluchistan border. Using long-range mortars a few dozen ad-hoc firebases could effectively control the entire border area with Pakistan's Tribal Area. (I have an annotated map with all of the firebases laid out if you'd like to see them) The cost of using such techniques is likely 1/100,000th that of using strike fighters as is the present absurdly expensive method. Unlike in Vietnam, where these firebases were static and absorbed a lot of manpower, these locations could be populated on demand as needed with a GREATLY dimminished logistical footprint.

As I have stated on this site several times. It seems our DOD procurement policies are designed to make infantry obsolete. I want to make them effective. Long-range organic indirect fire-support would be a huge step in that direction.

TWL:

I'm sure your design team knows this. But dobrodan reminded me that whereas there are many things hanging DOWN from the barrel, which is off-axis mass and tends to tip the barrel up, a Bren action, with the weight of the clip and ammo ABOVE, tends to offset the lower masses and makes for a nearly perfect distribution of mass about the line of recoil.

I wish you the best of luck with the new assault rifle trials. It sounds like you have gathered enough advantages to make replacement of the existing assault rifle worthwhile - if its chambered in Grendel, of course... :D

Yes, a good point about distribution of mass on the Bren.

However, we cannot use the top mag approach for our current design platform. Also, it is very "in the way" of the common sighting systems and optics used in modern weapons.

Actually, our approach currently is not to try to make a better machine gun, but to make a gun which can fill all combat roles competently, with minimum duplication of parts, lightest carry weight, least bulk, and maximum performance.

We recognize that purpose-built machine guns, or bolt action sniper rifles, or whatever, may have some edge over our wide-ranging design. But we feel that having the ability to field competent performing variations of almost all the typical infantry small arms, configurable from a single basic platform that everybody will carry, is a valid concept.

This concept allows any soldier to have any weapon at any given time. In the field, in minutes(or in seconds in some cases). As things are now, if your SAW goes toes-up, then your unit is out of a SAW until you can re-supply. With the modular platform, any soldier can plug on a beltfeed module and a bipod, and switch into open-bolt full-auto on the selector, and become a SAW gunner right now. And he can run 2 full belts immediately without so much as a cook-off from the carbon fiber barrel. And the system is quick-change-barrel, so even if he needs to run 10 belts continuously, any barrels can be changed in action, just like a SAW might be, but maybe a little slower.
Conversely, let's say you are on a mission which goes across some territory, and when you get there, you need to do house-to-house room clearing. You can have your duty length barrels in place all the way there, and switch to your shorty barrels at the AO when you get there for the task at hand. Or let's say you are setting an ambush, and you'd rather have 4 SAW's instead of one. No problem. Or perhaps you might find your SF fire team across a ravine from the target, and you might have the opportunity to hit several key enemy personnel at the same time, if you only had a couple extra sniper rifles. Well, now you do. You just slip out the duty barrel, slip in your 20" 6.5 Grendel barrel, change the bolt and mag, and put on your USO 10x scope in QD mount, and voila'.

Many scenarios could be played out, when you have versatility.
And remember, a couple of 1.7 pound carbon fiber barrels, and a few spare modules are not heavy loads to carry, for what you get out of the deal. Most of the main platform is utilized for all modular configurations. And with this platform, such as the one I have here in front of me now, it is fully loaded(30rd mag) with Aimpoint and cantilever mount, BUIS and flip-up FSB, weaponlight, sling, vertical foregrip, ready to rock and roll right now, at 7.5 pounds carry weight. In one minute's time, I can switch to my 20" ABS carbon fiber target barrel, and slide on my repeatable-zero mounted US Optics 10x scope, slip in a mag of 77gr Sierra match loads, and hit with deadly precision at 600 - 800 meters with no problem at all.(I'm accustomed to long range shooting). If I had a Grendel barrel, bolt, and mag, so much the better. If I had my 16" barrel on, and needed to do some tight-quarters room clearing, then I'd just put in my 10.5" barrel and go for it. Many people don't realize just how much can be done with a modular system like this.

TWL: That is one of the best summations of gas impingement vs. piston I have ever seen written, and I concur whole-heartedly! Kudos on calling it as you see it!

My humble thanks for your kind comments, Variable.
:)

I have great confidence your team understands the requirements. When I started writing I found I was writing viginettes, but as it turns out, this is exactly the same approach the Rand Corp uses to study weapon systems. The key point is you have to think not just about where your guys are now, but how you got here and where you are going - complete mission planning. Your designer's SOF background shows in the weapon he's developed.

IMO, the current SCAR supports inter-mission reconfiguration, but not intra-mission reconfiguration. While this allows a patrol through mountainous "Indian Country" in Afghanistan with a long-range configuration and a patrol the next day or week with a 7.62x39 short range configuration, it does not allow your DMR to replace your machinegunner if he is killed or wounded by converting his weapon right where his is with no need to maneuver to the MG gun or its position which is obviously under lethal enemy fire. The SCAR also does not allow an MG in perfect position to take out an enemy sniper to do so, or by contrast, a sniper provide suppressive or "pulling" MG fire because he just happens at this very moment to be in the PERFECT position to do so and no one else is.

Your weapon system should also allow large parts of the system to be replaced as needed if damaged or destroyed. In fact, not only can barrels be quickly changed, but many parts of the MG (as an example) can be replaced so that one spare MG conversion kit could be carried for each 2-3 MGs anticipating damage or malfunction and be used for added firepower by the DMR or other infantry if not otherwise needed. In short, your system not only supports intra-mission, but intra-engagement reconfiguration.

We shot 1,000 HARM missiles costing $750,000.00 each at SAM sites in Kosovo and got ZERO hard kills. At $000,000.35 per bullet that is 2.1 BILLION bullets worth. This is why the infantry should be made more effective, not obsolete.

If it were just the AK in the reliability department, I might agree with you. Unfortunately there are also the FAL, Galil, AUG, Tavor, etc. that use a piston instead of direct impingement. In fact if I am remebering properly, the M-16 platform is the ONLY direct impingement AR in service. I am not an "Expert" I am just an enthusiast. If that invalidates my read on the information I have, then so be it, I will shut up, sit down, and let the "Experts" argue it out and go on my merry way.

I would also like to point out that if direct impingment were the end all be all, then why are rifles like the FAL used by independant contractors who HAVE no government mandated TOE and can use any damn thing they want? All I have heard is that the FAL and weapons like it are some of the most reliable desert rifles available.

Feel free to tell me to butt out.

edit: Let me amend that. If there is a way of keeping the direct fouling from the ammunition out of the mechanism while still keeping the simplicity of the direct gas system, I would be all for it. I am not hooked on the gas piston, it just seems to be the proven solution to the reliability problem as I see it.

First, let me say that this is a discussion, and I'm not dictating anything to anybody. I'm just stating opinion, based on some experience with weapons design.

For the record, none of the weapons you mention can match an AR15 for pure accuracy. This is due to various things, including the effects of the piston systems. The FAL lost out to the M14 in trials, which was replaced by the M16 direct gas impingement weapon. The Aug lost out several times to the M16 in trials during the 1980's. The Galil was never under consideration, and I've owned several, and the accuracy is about like an AK, which is to say, poor. Tavor is new, and apparently the IDF prefers to use the M4, even though they make the Tavor.

I understand that pure accuracy is not the only thing involved in a combat weapon, and that these piston operated designs can be acceptably accurate in combat roles. However, it has been shown in 40 years of trials and attempts by these other rifle manufacturers, that have tried valiantly to unseat the M16 as the main US combat rifle, that they have not had the stuff needed to do it. They were all "clean running in the breech" because of their piston actuation keeping the gas in the handguard, but yet they could not beat the M16 overall. The FN SCAR looks like it may do it, and has received a minor contract, but still not for general issue.

Contractors may use whatever they wish, and 308 rifles are generally used when the ammo is required to do barrier penetration roles. There have been no 30 caliber rifles in general issue to any major country's forces for about 25-30 years. However, some of the basic design ideas were handed off to the smaller caliber variants of them. We still use the 308 in the M14 for some special duties, and quite a bit in sniper rifles.

I don't say that the M16 is a perfect weapon, or anything close to that. What I do say is that when discussing piston-operated gas sytems compared to direct-gas impingement inline recoil system of the M16, that it is my opinion that the direct gas impingement inline recoil system of the M16 will give better accuracy and satisfactory reliability in its required performance envelope in combat. It is not only where the gas blows out, but also how the weapon design functions mechanically, and has implications in accuracy and handling characteristics, among other things. Accuracy and better controllability can result in higher hit probability, especially at distances.

Now, let's look at the problem with the M16.
It is widely stated that the system "shits where it eats", which causes unreliability issues.
However, it is not entirely true. The M16 system bleeds gas off the barrel at the gas port, directs it back thru the gas tube to the carrier key, which feeds the gas down into a piston chamber inside the carrier which rotates the gas-ringed bolt out of battery for cycling. Excess gas is vented out two ports in the side of the bolt carrier, which exhaust that excess gas out the ejection port.
The gas rings on the bolt are designed to seal the chamber gasses from blowing forward into the breech area, excess gas is vented out the side of the carrier thru the ejection port, and any carbon-laden gasses that do deposit soot in the breech are blow-by effects.
Yes, it does look dirty and black after a few rounds, and it looks ugly.
However, we do know that even though it looks ugly, and we don't like to clean it, that the weapon will still operate reliably for many more rounds than a soldier carries with him, and for many rounds after he shoots an another extra full load out of ammo or more.
So, if the weapon does what it needs to to, and will continue to do it for more rounds than a soldier will possibly shoot at one time, then what is the problem?

Now, if you want to talk about adverse conditions reliability, that will directly relate to running clearances. The AR15 runs tighter than an AK, or a FAL, or a Galil, or an FNC, etc. So, when the going gets gritty, there can be stoppages with an AR15, before one would likely occur in, say, an AK.


Having a cleaning regimen that is 15000 rounds or more sounds real good on paper, but has no meaning in the real world. No soldier shoots 15000 rounds thru his gun without cleaning or checking parts for wear and failure indicators. You still have to clean and tear down and check parts conditions as part of normal maintenance on any gun. There is no such thing as a maintenance-free gun. So, since you are going to be performing routine inspection and maintenance at regular intervals anyway, what is the big deal about performing some cleaning it while you do it ?

To answer your last point about keeping the carbon deposits out of the breech in an AR15, correct maintenance of the gas rings, and keeping the fit of them tight on the carrier bore is central to that goal. The other thing is to keep the gas system from blowing more gas than is necessary into the system, and that is done with gas regulation. We make two different gas regulating systems for the AR, which allow tailoring of the gas, to overcome the problems related to advancing gas port erosion that takes place over time, especially in carbines. Shooting the gun for thousands of rounds, never replacing any worn parts, leaving it filthy, and general neglect of the weapon, are hallmarks of the average shooter. Blaming the weapon design for the results of this neglect is not where the blame should be pointed. If the gas port is severely eroded, the gas rings are worn down, etc, then it's not the fault of the design that the gun is terribly dirty.

Now, it is entirely true that a piston-operated design will have less carbon deposited in the breech area than a direct impingement system will. That, I do not dispute at all. However, I do question if the other things that come along with the piston system are worth the improvement in that area.

That's where opinions come in, and I've stated my technical reasons for having the opinion that I do.

As an ex-infantry, or actually cavalry-soldier myself, I must question the idea of dragging along spare weapons-parts on a foot-mission.

I used to be a machinegunner, and thereby my fire-team was burdened with, amongst others, a QCB and an extra bolt for the machinegun. The problem was not really the weight, but rather the bulk of the extra equipment.

I understand that all the military brass wants at least one beltfed in every infantry-squad. This has become a "standard" for almost all infantry-squads in all armies in the world.

The problem with beltfeds is that they often are not reliable enough, and if only one is available to a squad, then they are in deep trouble if something happens to it. Also, the squad often carries a lot of ammo for this weapon, which means that if its broken, they need to start unbelting the ammo for use in other weapons.

My solution to this would be to use three man fire-teams, where you have one man with an automatic rifle, one man assisting with mag-changes, and one team-leader communicating with the squad-leader and providing security to the fire-team. When the assistant is out of AR-ammo, he switches positions with the team-leader.

This way, an infantry-squad could have as many as three or four automatic-weapons, which means they could coordinate their fire much better, and be able to fire more accurately, while not getting as much attention from the enemy as a beltfed would have gotten.

This way, the soldiers of the squad would be able to stay much more "streamlined" when combat-ready, thereby being able to move faster, especially in FIBUA, where your life often is dependent of how fast you can move. If the magazines of the automatic rifle and the assaultrifles are interchangeable, this could mean a lot for QCB, as automatic rifles could accept large capacity mags, and thereby be able to function as "micro"-machineguns under given circumstances.

About barrel-lengths, I believe for an automatic-rifle, the standard-length should be around 18", while for an assaultrifle 14-16" should be sufficient.

(If shorter barrel-lengths are needed, a SMG with the layout of an UZI, would be to prefer, enabling left- and right-side use, while still gaining a few inches of barrel-length compared to a classic layout. But armor-piercing ammo should not be used, rather large calibre "slugs".)

About accuracy of piston-systems, Im sorry to inform that somehow, some of the best marksmen Ive encountered in the military is the Finnish. They carry their Sako 76/95 AK-clones in 7.62x39, and somehow, still, they are able to win multi-national military shooting-competitions.
Some of the worst marksmen Ive seen were American soldiers. But, I dont think they were actual infantry... Rather REMFs and reservists.

Most soldiers dont need a superaccurate weapon. They need a superreliable weapon.
Being able to hit an enemy in the head at 500m is nice, but what is more needed is to be able to kill ten enemies at 50m as quick as possible. While the first is possible on a shooting-range, it gets a lot more difficult in the field after running and sweating for a while, and especially when under fire.

I certainly agree that magazine-fed full-automatic fire is useful and desireable. Also, that it my be more reliable in certain circumstances. And full mags are certainly more interchangeable with the other weapons, than a belt would be. All good points. Thankfully, our system does not require the use of the belt fed module for anyone that doesn't want to use it. Magazines can be used, and are still the primary feed device for anything in the system, except when the belt-feed module is specifically selected and installed for a purpose. This would provide a way to use the gun with the 3-man team that you proposed above, and use magazines as you describe.

Regarding carrying additional modular hardware, this may be a burden, or a blessing, depending on the circumstances. It would not have to be a requirement, but could be a valuable option when needed in foreseeable situations.

As weapons designers, we try to provide the most useful equipment that we can, in the hopes that the troops will benefit. We can't control exactly how they will use things, but we do hope that we will give them something more than they had before. If I provide some additional thing for them to carry for optional use, I like to make it as lightweight, small, and high-performance as I can make it. For example, our carbon-fiber replacement barrels weigh less than 2 pounds fully-outfitted with FSB, Flash-hider, and gas tube, and are slim(folding front sight) tubes that can easily be slid into a ruck. Maybe troops won't want to carry them. We can only hope that our designs will be viewed as an advantage to those who can understand how to employ them effectively.

Regarding marksmanship and the accuracy of the weapons platform, this is a debate that has endured for a long time. Some people want to provide accuracy and distance, and others want to provide short range blasting. We try to provide a way to have both, by using modular systems. And it is true that a good marksman with an average weapon can often shoot more accurately than a lesser marksman with a very accurate weapon. This is the way of the world. But, we hope to provide an accurate and versatile weapon so that good marksmen can achieve their best results. In a world where body armor is becoming more widespread in many militaries, it results in a need for either a more powerful caliber to defeat the ceramic hard-armor body plates, or defines a smaller target area for the successful shot. To me, this means accuracy is essential, or the shot will be defeated by the body armor(with existing small arms calibers).

Currently, a belt-fed variant of the small arm is a requirement by the US specifications for the advanced combat weapon. We are complying with that requirement, but not precluding use of magazine-feed on the same weapon.

The USAF tried for decades to combine the roles of fighter and strike aircraft and finally in ODS the efforts paid off. F18 and especially F-15 Strike Eagles were able to do deep penetration missions and on several occasions had to stop and dogfight MiGs to get in. They were able to defeat the MiGs without dumping their bombs and then continue on their missions. StrikeEagles in particular flew alone - not part of "packages" of CAP and SEAD and strike aircraft. They flew alone and did it all themselves. Interestingly, the StrikeEagle was still in testing when ODS started so this was a baptism by fire. The USAF and Horner in particular said during and after the war "get me more StrikeEagles!"

From the point of view of a mission planner I see some of the same force multiplier potential in your weapon system. One can plan extended missions, with cache or aerial resupply, and plan in advance what configurations of weapon should be needed for the various sub-missions. This is in contrast to having to send in many more specialized units that have to linke up, coordinate, and try to remain concealed so as not to risk engagement by an overwhelming enemy force. All of this coordination is frought with danger as there are just too many failure points. Part of the resupply, given field computers and PGM resupply pods could be spare, or replacement parts for the weapons.

If your weapon in fact wins the contract, I can see future historians pointing to this moment in history as an important turning point. Freed of heat buildup problems, appropriate configurations, and weight issues, infantry will need to be better trained (as strikefighter crews need to be) and will likely do better if considering some of the issues currently left to higher command as they will be called on to fulfill more roles - perhaps in the same mission.

Now, about grenade launchers...... ;)

Here's a couple of new shots showing a little clearer view of what the MGI Modular Lower system looks like.

http://photos.ar15.com/WS_Content/ImageGallery/Attachments/DownloadAttach.asp?sAccountUnq=53166&iGalleryUnq=1956&iImageUnq=42628


http://photos.ar15.com/WS_Content/ImageGallery/Attachments/DownloadAttach.asp?sAccountUnq=53166&iGalleryUnq=1956&iImageUnq=42629


Please note that the removeable magwell is installed/removed vertically via a beefy precision dovetail mounting system. Also note that the area around the hammer pin is beefed-up with a boss and the entire area strengthened for use with the open-bolt FCG. Also note that the removeable magwell captures the hammer pin for anti-walk function. Full fence around the mag release button. Unit is held captured at the top by the upper receiver and front hinge-pin, and at the bottom by the triggerguard pin(fully triangulated mount, and precision dovetail mating.

Serial number is stamped on rear half of the lower receiver, and caliber is stamped "Multi".

These early units are manufactured for MGI by CMT/Stag Arms. Later, they will have only the MGI logo on them, but will still be made by CMT.CMT is capable of producing in any quantity, all the way up to general Army issue quantities.

Slick, huh?!

When used in conjunction with the MGI QCB(Quick Change Barrel) upper receiver, you have a completely modular rapidly-configurable caliber changing system that uses common existing hi-cap mags for the caliber you want. Just swap barrel, or barrel and bolt, or barrel/bolt/mag, depending on the caliber changes you want. Soon to come are 9mm, 45ACP, rimfires, and others.

Photos of AK magwell will come as soon as I get them emailed to me from the MGI main office.

Oh! And by the way, here's a photo of the MGI QCB upper, if you've never seen one yet.
http://www.mgimilitary.com/images/CompleteRifle.jpg




And here's a pic of an ABS carbon fiber barrel in an MGI QCB(mine :D )
http://photos.ar15.com/WS_Content/ImageGallery/Attachments/DownloadAttach.asp?sAccountUnq=53166&iGalleryUnq=1956&iImageUnq=37737

And one of the ABS carbon fiber barrel assembly, removed from upper.
http://photos.ar15.com/WS_Content/ImageGallery/Attachments/DownloadAttach.asp?sAccountUnq=53166&iGalleryUnq=1956&iImageUnq=37736


You see! All this stuff actually IS real!

TWL wrote: "I've stated my technical reasons for having the opinion that I do."

Well-spoken, and convincing — and I'm a gas-piston fan! Your comment about the tolerance of grit interested me. Do you think there's any way to "loosen" the tolerances in an AR receiver, such as to machine grooves in the carrier to give grit some place to go, or some such?

John

Grendelizer,
We are working on an improved bolt carrier which we hope will address some of those problems. Also some improvements on our already highly acclaimed RRB buffer design. Probably be a little while before we get that out, because we're busy with all the stuff shown above right now.

And again, if it shows that the market wants a piston operating system and won't stay with the direct impingement design, then we have piston operating system designs ready and waiting for that possibility. And they all can work fine along with our current modular weapon design. While I may have my opinions, I cannot afford to be so dogmatic about it that I ignore the desires of the market.

I'd also like to add, that I've been in contact with Alexander Arms about becoming a licensed vendor for a 6.5 Grendel barrel/bolt/mag package to provide our MGI modular users with the advantages of the 6.5 Grendel caliber. As soon as they approve this, we can start offering it.

Just out of curiosity, would it be possible to free float the barrel in front of a gas piston? Basically have the barrel tensioned or locked into a rigid collar that attaches to the reciever, basically extending the mounting of the reciever out past the gas piston assembly, and run the gas piston in that "framed" area, thereby minimizing any effect the piston might have on the accuracy of the barrel?

Just out of curiosity, would it be possible to free float the barrel in front of a gas piston? Basically have the barrel tensioned or locked into a rigid collar that attaches to the reciever, basically extending the mounting of the reciever out past the gas piston assembly, and run the gas piston in that "framed" area, thereby minimizing any effect the piston might have on the accuracy of the barrel?

Theoretically speaking, it would be possible to do that, although they don't call that "free floating", but instead "rigid mounting". But many practical aspects would make it difficult to implement in practice on an AR type platform. Bullpup designs have been made like that.

In all fairness, the accuracy issues that occur with the piston designs are not so heinous that they couldn't be used for typical military accuracy levels of 2MOA, in a good implementation, or maybe even better than that. Perhaps I came down a little hard on them, because I'm constantly involved in the "hype wars".

However, I will take this opportunity of mention another aspect of the piston design vs direct gas impingement that I neglected to mention before. In the direct gas impingement AR15 system, the bolt is rotated into unlocking in a manner that is directly inline with the bore axis, with the gas pressure forcing the bolt forward at the same time as the carrier is being forced backward in a manner that is directly inline with the bore axis. This helps to reduce the shearing load on the lugs during unlocking. In the piston system designs, the carrier is pushed at the top of the carrier key, which is well off-line from the bore axis. The forces are no longer uni-directional, but are now a combination of rearward and angled forces, which place loading on the bolt carrier to lift in the front, and be pushed downward at the rear. Depending on how the mods to the bolt carrier are done in these piston systems, this can result in angular forces being present at the bolt during unlocking, which can cause accellerated wear or even breakage of the bolt lugs over time. And also perhaps some wearing in other areas not normally seen in an AR. Also, the bolt is basically just dragged out of lockup by the cam and cam slot in the bolt carrier as it is thrust to the rear by the op rod. There is definitely a difference in being unlocked by the inline rotation method, than there is with an overhead op rod pushing the carrier key.

While I will concede that there is less carbon in the breech from a piston operating system, it really gives me pause when I see all these other issues. All we can hope is that these piston system makers did a good job, and knew all the issues that they were facing.

I can see your point about the op rod/bolt carrier situation. Thats why one of the designs I am looking at as a base line is the M1/M14/Mini-14 op rod system which seems to be somewhat simpler than trying to redesign the AR bolt carrier for piston op rod use. One of the other reasons is that there is a company (Accuracy systems inc.) that routinely takes stock Mini-14/Mini-30s and using a combination of better bedding, stiffer barrels, etc. have gotten them down below the 1 MOA accuracy level. Admittedly this is in semi auto firearms, not assault weapons, but thier technology and techniques could theoretically be applied to any weapons design, just like adding a carbon fiber reinforced barrel, or a cammed barrel lock at the breach for quick change barrels.

The other reason I am looking hard at this type action is that it has constantly proven to be favored by the Designated Marksmen and Sniper crowd as a semi automatic tack driver (and if the M1 had been originally chambered for the "Pederson" round, we might not even be having this discussion as the eventual development of the round might have lead to somthing similar to the grendel, and the upgrade of the M1 to the M1A/M14 would have gone more smoothly as full auto would have been SIGNIFICANTLY more controllable).

I'm a fan of the M1A, and I've had many of them, and used them in highpower competition. They can be very accurate, indeed. Complex bedding work, which only lasts for awhile, is the big issue there. I've tuned alot of M1A rifles, and it is a bit finicky, but they shoot real well when they are set up right. I took second place in the Florida State Championship 600yd prone match with an M1A, during the 1990's.

check out Accuracysystemsinc.com and see what they are doing with the mini-14/30s. They use Steel bedding to avoid the wear and tear issues. Also, they have a grendel conversion.

Interesting!
One thing that I got a kick out of was their barrel harmonic stabilizer unit.
Looks pretty cool.
In fact, it looks like the same thing as this:
http://www.funsupply.com/Firearms/_derived/mwg.html_txt_accuriz.gif
Just so happens that MWG stands for Mack W. Gwinn(it's one of Mack's earlier ventures), and we introduced that item to the world about 20 years ago. We no longer make it. But, it does work, and I'm glad somebody is getting some use out of the idea. :)

I also noticed that they do M1A/M14 upgrades as well, I'm not sure about bedding, but I know they have an H-Bar conversion down near the bottom of the "Mini-14/30 conversion prices page"

Back to the subject at hand.

I will admit that the action has its flaws (weight being one of them), but it is concevable that with a "modernization program" you could make the Mini-14/30 every bit as accurate, reliable, and user friendly as the AR-15, as well as make it work as a full auto combat arm like the M-16. First thing I would do would be to replace the spring with a stiffer one, and drop some weight from that op rod...them suckers is HEAVY for that rifle. Modern materials for the stock and trigger group would be next (with bedding you don't have to depend on your trigger group to hold the reciever in place in the stock), different bedding attachment design for quick release/cleaning/reassembly, and for heavens sake, figure out some way to make the piston self cleaning (probably not doable, so a fast replacement would be good too).

Okay, enough of my ranting. Back to the experts ;)

You're killing me TWL - I'm gonna have to start saving for your stuff and another (or a bigger) safe right now.

Are your upper forgings from CMT as well?

You know, I was just thinking...its too bad I don't have an M14/M1A or the blueprints to compare to the Mini-30 I have. I have a feeling I would be better served by shortening and developing the action of the M14/M1A than trying to solve all the issues with the Mini-14/30 action.

You're killing me TWL - I'm gonna have to start saving for your stuff and another (or a bigger) safe right now.

Are your upper forgings from CMT as well?

Yes, the upper forgings are from CMT, and we make the QCB locking block and railed FF tube parts ourselves. The upper is specially made for us, and has timed threads for proper indexing of our locking block onto the front of the receiver.

The upper forging is machined internally with the "AR47" reliefs in place, so that the upper will accept the correct positioning of the AK47 magazine for proper operation. The AK mags need to sit up into the breech area of the upper, and are wider, so they need a bit of extra room machined into the upper receiver internally. This is all standard in our MGI QCB upper receiver now, and it will be a perfect match with our new MGI Modular Lower as a multi-caliber system. AK74 mags will also work in this magwell.

We will also have the correct bolt carrier dimensions that will work with both types of magazines. The AK mags require some clearance cuts in the bolt carrier to allow it to work over the feed lips of the AK mags.

These reliefs will also allow other wide magazines to be used with other magwells, and we are looking forward to releasing magwells in 45ACP(grease gun mags) and 9mm(Sten or Sterling mags) in the near future. Our system makes it easy to use the pistol calibers without having to install a mag block for them like it used to be. Also, our pistol caliber options will have gas operating systems, and will not require changing out the fire control group when you go to a pistol caliber. Quick change.

Additionally, although this option will come much later, we can put a longer 308-length magazine well on this lower, and use a modified AR10 upper on it to allow bigger calibers to be used on the same lower. So theoretically, you'll be able to use anything from .17 cal to .458 cal on this lower, albeit sometimes needing the larger upper receiver for some of these calibers.

http://www.65grendel.com/forum/showthread.php?t=320

TWL,

If that scale is showing weight in pounds for your CQB rifle, you have just fulfilled another prediction. Unfortunately, due to some bad legal advice, I deleted my thread initiating post, (and about 150 others :mad: ) but the technological basis was there and it looks like ABS has fulfilled it. :D

Solidpoint,
actually that weight on the scale showing 3.68 pounds is for the complete barrelled upper, not the whole gun. We're light, but not that light! I wish the whole gun was 3.68 pounds!

We do have some other weight saving measures aimed at our upper, which should shave off another 8-12 ounces from it, and that will be pretty darn light to have an upper at(or under) 3 pounds, with an HBAR profile barrel. Right now, my gun is well under 6 pounds in iron-sight configuration, unloaded, and no accessories on it. It is right about 7.5 pounds fully loaded with 30rd mag, Aimpoint and cantilever mount, BUIS and flip-up FSB, weaponlight, vertical foregrip, and sling, ready to rock. Soon, we'll get that same config down to under 7 pounds, but I think that's pretty close to as light as we'll get. At least in this iteration.

Here's a photo link to the AK magwell for our MGI Modular Lower Receiver system. (photos of that are a couple pages back in this thread).

http://photos.ar15.com/WS_Content/ImageGallery/Attachments/DownloadAttach.asp?sAccountUnq=53166&iGalleryUnq=1956&iImageUnq=42662

In the white before final edge cleanup and finishing. The one on the left is the production model, and the one on the right was the original prototype. Note that there is a mag BUTTON and not a lever! This also allows the mag to eject out on its own, and you don't have to rock it out like on an AK!
Also notice the nice fence around the mag button, and the beefy construction all around.
Works with AK47 mags or AK74 mags.

Right now, my gun is well under 6 pounds in iron-sight configuration, unloaded, and no accessories on it.

Sounds about right. I built an ultralight upper using a Bushmaster superlight barrel, a carbon fiber free float tube, a Les baer forged aluminum flattop upper w/o forward assist and a heavy chrome DPMS slick side (no FA cuts) bolt carrier. It weighs in at 3 lb 9 oz. A 27 oz. Cav. Arms Mk II lower brings the total to 57 oz or 5 lb 4 oz. I could have shaved off a few more ounces by cutting the barrel and having the flash suppressor permanently attached for a 16" OAL, using a barrel w/o a flash suppressor, using a Colt open-back carrier and/or a carbon fiber upper.

IIRC with one of your standard 16" barrels my carbine's weight would be about the same, but it would be more accurate and would handle heat better.

I think 3 pounds is about the limit for a forged aluminum M16/AR15 upper with a 16" 5.56 upper with a superlight steel or standard profile ABS barrel, but I'd be happy to be wrong.


Now, if you want to talk about adverse conditions reliability, that will directly relate to running clearances. The AR15 runs tighter than an AK, or a FAL, or a Galil, or an FNC, etc. So, when the going gets gritty, there can be stoppages with an AR15, before one would likely occur in, say, an AK.

Now this got me thinking:

1. Unitized stock/receiver molded from carbon or glass reinforced resin (with metal reinforcements where necessary) maybe with a top/dust cover like the Stoner/ARES FARC-3
2. Free floated or tensioned barrel for accuracy
3. PLENTY OF OPERATING CLEARANCE inside the stock/receiver
4. Johnson/Stoner lugged bolt
5. Direct gas impingement
6. Bolt carrier running on symetrical (6 and 12 or 3 and 9 o'clock) guide rails (to minimize axial forces).

One reason Stoner did not use direct gas impingement for the AR16 and Stoner 62 (according to The Black Rifle) is Colt owned the related intellectual property. Now that the patent has expired, you could put the bolt carrier on guide rods to get rid of the rear half and the buffer (reducing weight) and the bolt carrier/upper receiver interface (increasing operating clearances). That formula should preserve the accuracy advantages of the M16/AR15 while enhancing operating clearances and reliability.

Ironically, the XM8 is descended from the AR16 via the AR18 and G36.

TWL:

Not directly on-topic, but to get your attention:

Wouldnt your carbon fiber technology work extremely well with a M2 .50 barrel?

My own experience with the M2 machinegun has told me that there is a bit of room for improvement, and a lot would be accomplished by removing the need for a QCB, because its very time consuming, and also dangerous under fire.

I believe this could be very easy to accomplish, and if the price is right, I believe it could be a "killer" product for your company, being able to attract a lot of attention to your other products from both civilian and military buyers.

Yes, we make 50BMG barrels in our carbon fiber barrel system.
We have not used them for military application yet, but they are used on civilian long range rifles in 50BMG.

We still have not penetrated into the military markets much.
There are some military units and law enforcement using our M16/M4 barrels, but nothing larger than that yet. Even these units only have small numbers which are basically trial and evaluation quantities. But we are hopeful that we'll get further into military usage. Cost is an issue here, and our barrels cost alot more than regular ones.

We also provide our carbon fiber application on the 408 CheyTac long range rifles, as a factory option.

http://www.mcwl.quantico.usmc.mil/ecp/5-Initiatives/GCE/ECP-HMGTDI-22%20Dec%2004%20Web.pdf

This looks like it could be a good use of your CF technology - applied to both the weapon and the mount. The added cooling would not be needed for the mount, but in combo, the total weight savings could be substantial AND it would get you into the barrel mfg arena.

:D

I just had an idea of how to make a bullpup weapon "ambidextrous"

The biggest problem with a normal bullpup is that its not ambidextrous, and a solution like FNs F2000 may be too complicated and get jammed with snow or dirt.

Secondly, there are a few shooters that dont like the idea of a round going off next to their heads...

And last, they are slow to reload because of the awkward positioning of the magazine.

The solution to this would be to make a bullpup that can change the side of ejection without the need of disassembling the weapon, while keeping the chamber as far as possible from the shooters face.

If the magazine is located just behind the pistolgrip, it could interfere with the shooters thumb.

To be able to locate the magazine as far forward as possible, a feature from the M-249 could be adopted, a magwell at a 45deg angle.

This will not necessary do anyting good for southpaws, but if you include an ability to rotate the magwell inside the "frame" of the gun, and thereby the receiver and the bolt, 90degrees, you could change it from right to left in a matter of seconds.

You would only need a deflector on each side of the top, to keep the brass from traveling in a too high arch.

To unlock the receiver you could use the safety, by just pushing it past safe, and thereby letting you slide the pistolgrip forwards to let the mag pass freely...

This could be too complicated and too expensive to make, but it could be a solution for bullpups...

Dobrodan,
Pretty cool idea!

Mack Gwinn had a similar idea back in the early 1970's when he produced this Bushmaster unit. The pistol-grip portion rotated side-to-side, which allowed use right-handed or left-handed. However, in this unit, which was sometimes called the "Arm-Pistol" it had top ejection which would need an adjustable deflector for the ejection, depending on which side you were shooting from, off the shoulder.

You just hold the pistol grip in either hand, and rotate the magazine portion inside your arm, and it ejects outwards, and the magazine is resting inside your arm. It was an evolution of the old Colt "Imp" project from the 1960's.

Mack has been talking about re-introducing this design, with some updates.

http://www.biggerhammer.net/armpistol/bushmaster_rightside_mag_web.jpg

Thanks!

The similarities are clear, but my idea would probably be superior in accuracy, because it would allow long-range accuracy, not least because rails could be added to mount optical sights.

However the Mack Gwinn design would IMO be nearly perfect for QCB and Fibua, as it is extremely minimalstic in design, but still incorporates a relatively long barrel.

Also, the CG could be placed further forward, because the chamber can be located above the pistolgrip.

Dobrodan,

I am trying to visualize your idea. As best I understand it I think you are onto something.

As an aside, it is possible to have a bullpup with a magwell ahead of the trigger assembly. I got this idea when discussing the Winchester 94 in Grendel with EssaysOn. One could design a short tubular "shuttle" tube using an axial feed/auger, and a ribbed tube to move something like 3-4 shots from the forward clip backwards under the trigger/handgrip and back to the reciever. One nice benefit of this would be having 3 "last ditch" rounds in the gun when the mag is empty. A mechinism would be needed to load the entire 3 rounds when charging a completely emptied gun. Such a gun should have great balance as the added weight would be right in your hand. Freed of the need to place the magwell in a more ergonomic position, it might also be possible to move the reciever even further back.

Unfortunately, I cant figure out a way to put a picture in here, but Ill try to explain a little bit:

If we look a little bit closer at TWLs picture, we could first cut loose the receiver part, and move it 5cm forwards. To allow that, the receiver can be twisted 45degrees to either side, so that the mag doesnt interfere with the pistolgrip.

The pistolgrip, barrel and forearm is rigidly connected to an upper that is extending back towards the butt. The receiver is supported by a sliding cylinder in the same axis as the barrel, to allow rotating the receiver.

To rotate the receiver, you simply push the safety upwards, slide the pistolgrip forwards, push the magazine over to the other side, and slide the pistolgrip back into position, release the safety, and you are ready to fire from your other shoulder.

I understand what you are describing.
It could definitely work.
It seems to be popular now to have a short muzzle length, so the guns can be shot from inside HumVees and things.
Might be a desireable layout.

So basically we're talking a cross between an FG-42, a SAW and a typical bullpup (45-degree magazine feed slightly behind the pistol grip with a provision to change the position of the mag to accomodate left or right handed use)? Neat idea. Ejection still might be an issue.

IIRC the FG-42 was unbalanced by the 10 or 20 round mag full of full power rifle ammunition hanging off the left side, but a lighter mag angled downward might work.

If the military wants shorter barrel lengths, then IMO they need to address the whole system to maximize velocity and minimize muzzle flash given the barrel length requirement.

been working on the top loading bottom ejecting design with the P90 mag. Shortening the mag to 25 rds I got the PDW/SMG version shorter than a P90. Also, the barrel to sight line is about the same height as the P90 or an AR15. Perhaps something similar, or perhaps dual mag feed/rotating mag feed like you described. The feed to eject system would be a Y shape with the tops of the Y being the feed direction, and the bottom being the ejection port. I also "test fit" a beta mag modification on a SAW variant design and it worked pretty well. Eventually I would like to design a belt feed mech that would fit in place of the magazine and be actuated by the piston system.

Is that an M1 Carbine/Mini-14 inspired operating/fire control system, Coolhand? I still haven't read the whole thread, but your picture suggests a cutoff-and-expansion gas tappet system driving a Carbine/Mini-14 operating rod and bolt. IIRC the fire control looks similar, too.

A M1 Carbine/Mini-14 style operating system would be nice for a bullpup because they minimize the length of the action behind the magazine port. I remember messing around with a copy of Ian Hogg's Small Arms of the World and some tracing paper in the '80s to come up with a downward ejecting bullpup with a top-mounted (Calico Style) helical mag based on an upside down Mini-14 action. A Beta C-style saddle drum might also work (if you could get a cheek weld above/ahead of it), but I like your P90 inspired system.

Your design looks like it would lend itself to a Stoner 63-type system - A bullpup infantry weapon and a more traditional belt fed variant with a rear-mounted trigger actuator and traditional butstock.

I'll try to digest the whole thread this weekend...

Suggestion for TWL I was reading about the development of the 30-round M16 magazine in The Black Rifle or The Black Rifle II. It said the original and more reliable design had a constant curvature. It would not fit in some M16 magazine wells, so they went to the less reliable part-straight part-curved design. It occurred to me that your modular lower, if adopted, would permit you to design a mag well that would work with both current USGI mags and a more reliable constantly curved version of the current generation of "high reliability magazines."

As I have mentioned before, I have some experience with the M2 machinegun. I have however never fired it the traditional way, holding the spade-grips. Ive been using a soft-mount, which increases accuracy, especially when firing bursts, because it absorbs the recoil, and has a shoulder-support-rod.

This could probably be used for some assault-rifles as well, but should be simplified a bit, because the same amount of strength isnt needed.


The weapon would then be consisting of two units:

One softmount consisting of handguard complete with rails, pistolgrip with trigger, top-rail for sights, and butt.

A stripped down, ultra-light rifle, without pistolgrip or trigger.


The rifle should be able to slide back and forth inside the softmount, letting some kind of buffer or spring absorb recoil.

This would probably fit well with my earlier mentioned left/right bullpup-idea...

This could of course mean that the weight would be untolerably high, but If the rifle-part can be made light enough, It should be endurable...

Dobrodan,

I am trying to visualize your idea. As best I understand it I think you are onto something.

As an aside, it is possible to have a bullpup with a magwell ahead of the trigger assembly. I got this idea when discussing the Winchester 94 in Grendel with EssaysOn. One could design a short tubular "shuttle" tube using an axial feed/auger, and a ribbed tube to move something like 3-4 shots from the forward clip backwards under the trigger/handgrip and back to the reciever. One nice benefit of this would be having 3 "last ditch" rounds in the gun when the mag is empty. A mechinism would be needed to load the entire 3 rounds when charging a completely emptied gun. Such a gun should have great balance as the added weight would be right in your hand. Freed of the need to place the magwell in a more ergonomic position, it might also be possible to move the reciever even further back.

I have given this idea some thought, and though it would probably work, it would probably be less than practical, not least because if you fail to count your rounds in a fire-fight, you could be in deep trouble, and it would still eject in the rear, which in my opinion is the biggest problem of bullpups.

This would be something like a "backwards" FN F2000...

Is that an M1 Carbine/Mini-14 inspired operating/fire control system, Coolhand? I still haven't read the whole thread, but your picture suggests a cutoff-and-expansion gas tappet system driving a Carbine/Mini-14 operating rod and bolt. IIRC the fire control looks similar, too.

A M1 Carbine/Mini-14 style operating system would be nice for a bullpup because they minimize the length of the action behind the magazine port. I remember messing around with a copy of Ian Hogg's Small Arms of the World and some tracing paper in the '80s to come up with a downward ejecting bullpup with a top-mounted (Calico Style) helical mag based on an upside down Mini-14 action. A Beta C-style saddle drum might also work (if you could get a cheek weld above/ahead of it), but I like your P90 inspired system.

Your design looks like it would lend itself to a Stoner 63-type system - A bullpup infantry weapon and a more traditional belt fed variant with a rear-mounted trigger actuator and traditional butstock.

I'll try to digest the whole thread this weekend...

Suggestion for TWL I was reading about the development of the 30-round M16 magazine in The Black Rifle or The Black Rifle II. It said the original and more reliable design had a constant curvature. It would not fit in some M16 magazine wells, so they went to the less reliable part-straight part-curved design. It occurred to me that your modular lower, if adopted, would permit you to design a mag well that would work with both current USGI mags and a more reliable constantly curved version of the current generation of "high reliability magazines."

Thats exactly the inspiration I was using. Instead of the old piston, an easily removable (cleanable) tappit unit, and the op rod similar to the Mini14. There are a few changes which I will not go into (as I may want to patent the design later) but basically you hit the nail on the head. Also, with the "op rod" extending down the side, a few changes to the amount of energy imparted by the gas port and machining in a few notches in the operating rod, and I should be able to develop a belt feed that slaps in similar to a magazine...which makes belt swapping and switching to mags a breeze.

Dobrodan,
Pretty cool idea!

Mack Gwinn had a similar idea back in the early 1970's when he produced this Bushmaster unit. The pistol-grip portion rotated side-to-side, which allowed use right-handed or left-handed. However, in this unit, which was sometimes called the "Arm-Pistol" it had top ejection which would need an adjustable deflector for the ejection, depending on which side you were shooting from, off the shoulder.

You just hold the pistol grip in either hand, and rotate the magazine portion inside your arm, and it ejects outwards, and the magazine is resting inside your arm. It was an evolution of the old Colt "Imp" project from the 1960's.

Mack has been talking about re-introducing this design, with some updates.

http://www.biggerhammer.net/armpistol/bushmaster_rightside_mag_web.jpg


Can you help me get in touch with him? I have been curious about that gun for a decade!

Sure, just call me at 1-800-307-0728.
I'm the MGI factory rep.

Thanks,
Tom Lyons
MGI

To be fair, the Bushmaster Arm Pistol was inspired by a Colt design commissioned by the USAF: the GUU-4P "IMP".

To be fair, the Bushmaster Arm Pistol was inspired by a Colt design commissioned by the USAF: the GUU-4P "IMP".

From my quote in my previous post:


"Originally Posted by TWL
Dobrodan,
Pretty cool idea!

Mack Gwinn had a similar idea back in the early 1970's when he produced this Bushmaster unit. The pistol-grip portion rotated side-to-side, which allowed use right-handed or left-handed. However, in this unit, which was sometimes called the "Arm-Pistol" it had top ejection which would need an adjustable deflector for the ejection, depending on which side you were shooting from, off the shoulder.

You just hold the pistol grip in either hand, and rotate the magazine portion inside your arm, and it ejects outwards, and the magazine is resting inside your arm. It was an evolution of the old Colt "Imp" project from the 1960's."


Recognition was given.

Recognition was given.

My apologies. I saw the first sentence and missed the last.

FWIW: Stanley Silsby and Dale Davis deserve to be recognized for their efforts.

I am aware of a Mr. Silsby who patented a "dial a punch" full-power grenade launcher to be used like an M79 ( you may have pointed it out to me here on this site, don't recall now ..) but am curious about Dale Davis. What is he to be credited with? TMVIA :D

Dr. Dale M. Davis' patents (http://v3.espacenet.com/results?sf=a&FIRST=1&CY=ep&LG=en&DB=EPODOC&TI=&AB=&PN=&AP=&PR=&PD=&PA=&IN=%22davis+dale+m%22&EC=&IC=&=&=&=&=&=)

More Davis patents (http://v3.espacenet.com/results?sf=a&FIRST=1&CY=ep&LG=en&DB=EPODOC&TI=&AB=&PN=&AP=&PR=&PD=&PA=air+force&IN=%22davis+d%22&EC=&IC=&=&=&=&=&=)

Stanley Silsby's patents (http://v3.espacenet.com/results?sf=a&FIRST=1&CY=ep&LG=en&DB=EPODOC&TI=&AB=&PN=&AP=&PR=&PD=&PA=&IN=silsby+stanley&EC=&IC=&=&=&=&=&=)

More Silsby patents (http://v3.espacenet.com/results?sf=a&FIRST=1&CY=ep&LG=en&DB=EPODOC&TI=&AB=&PN=&AP=&PR=&PD=&PA=&IN=SILSBY+S&EC=&IC=&=&=&=&=&=)

Davis was the Technical Director at the USAF's Armament Laboratory (Elgin AFB). He came up with the arm pistol concept and patented it. At Colt, Silsby refined the concept into the IMP.

Why is not this design (http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=CA924144&F=0) in common use? It appears superior to the drum magazine.

What about the "horizontal" drum. I seem to recall a WW1 machinegun (I belive a Maxim design) that was air cooled and either fed from a top mounted magazine, or a drum that rotated the rounds laterally (like the .22 cal American 180 machine carbine) instead of parallel to the bore (like a thompson drum or a beta dual drum). The benifit I see to that is you don't have the big "bren mag" sticking up, or a double cylindar on either side like the beta mags or saddle drums, and on my design it would fit in the same space as the 30rd mag design I am working on, sliding in and out from either side with very little or no modification to the rail design for the sights.

One of my earlier design iterations used a removable piece on the back section of the rail to allow usage of standard AR mags in a bren configuration or beta mags as a saddle drum. While good in a pinch, I felt that it made the sighting rail a bit...flimsy as it would be supported only at the front of the reciever and not at the rear. I just felt that any leverage would probably screw up the rail. While keeping the idea (for the afformentioned pinch where you HAVE to use non standard or previously standard mags) I still think that there has to be a more "elegent" solution than the beta style saddle or "belt feed" modual for the high capacity ammo system for use with a SAW/Automatic Rifle.

Also, I would like to know if anyone knows of a full auto system that uses a freefloating barrel without gas operation. I already know of the HK roller delay system, and I know the french use a Wedge or block delay on the FAMAS family, I was wondering if there was anything else out there that might be as good or better.

Okay, the Lewis Machinegun had the horizontal drum or Pan magazine. Since then there have been a few other including the current AR-180 from Dick Casull. Hmm, now all I have to do is figure out how big a 100 rounds of 6.5 G would be in one of those....

IMO, the main problem with the large pan-magazine is the sheer bulk of it, which makes it difficult to carry, and will also add a lot of weight which is not really necessary.

The combination of weight and shape may severely complicate mag-changes, because muscle-memory wont be enough to insert a new mag, thereby making mag-changes very time-consuming.

The shape of the magazines also make them diffiult to carry, and I would have preferred both drums and conventional mags, as they are much more compact.

The only place a pan-mag could have worked reasonably well is in a vehicle mounted gun, but there a belt-fed would have been a more compact and less demanding alternative...

Well, for the standard riflemen I was thinking a 30 to 50 round mag. The "pan" mag would be used to fit a hi-cap system in the mag slot without resorting to belt feed or chopping a section out of the sight rail to use a saddle drum, but still keep the top loading bottom ejecting design I am working on.

I still wish I could find a good, compact mechanism that I could use in place of gas operation to allow a true freefloating barrel. Yes I know the Ljungman system is an option (AR-design) but I do not consider it reliable enough for my tastes. I want XM8/HK416/G36/AK47 reliability, and a free floating barrel with an action no longer (behind the chamber) than that on a mini-14/mini30.

Dunno if its possible, but I'm still tinkering.

Hmmm, I wonder if I could develop a "half saddle drum" that would work...

Well, heres an idea I have been playing with for a while. Now of course these are "rough sketches", but basically its the "side load-top feed-bottom eject" design I have been workirg on mated with both the metal storm 40mm and a visualized 25mm version. I'd like to get your opinions. One additional benifit to using the 40mm tube is that the "rocket stick" of the standard RPG-7 family is 40mm and by using a separate insert on the launcher (instead of a 3 round grenade cannister), you could concievably use it as an RPG launcher and thereby increase payload diameter (and penetrating power) of your HEAP round.

... is also 40mm and shorter than an RPG. It is also F&F, 20" long, 5lbs, has a 2mile range and costs just $4k. At that range you would need the rifle host's scope - maybe with some fancy tweaks - to operate as a CLU. RPG's are for losers. They have a range not much greater than an M203, far less than an MK-19, terrible ROF, are unguided, and don't have sufficient penetration to defeat much.

Lest I miss my point, my thinking was your design might be able to accomadate a 40mm MetalStorm, NATO 40mm or SPIKE using a space reserved for a 40mm weapon.

http://www.designation-systems.net/dusrm/app4/spike.html

I was reading Daniel Water's site on the M16 development and it was interesting by contrast to the Grendel's development. There were over 200,000 rifles made before they even had bullets with the right powder, the ammo suppliers could not keep the bullets in spec, the few restrictions placed on the weapon and ammo were relaxed again and again so it could be fielded, etc, etc, ect. In stark contrast, EVERYBODY loved the 40mm grenade launchers and the M79 "blooper" was one of the most loved weapons of the Vietnam war.

To my eye this is one of your best designs yet. I like the GL on top, and co-located triggers. As long as the gun is in 6.5 Grendel and doesn't suck the weapon should work well.

PS: Just a reminder, but the penetration of a shaped charge grenade is a multiple of its diameter. This is due to the diameter of the hollow charge's cone. Therefore, even if carrying the same amount of charge, a 25mm is dramatically less effective than a 40mm. IIRC, the multiple is from 3-7x and you can half that for angled surfaces.

I was just talking launcher and warhead profile. If you can rig up the SPIKE to be used in the upper barrel of the AICW (the Austrailian OICW that I snagged the 40mm tube off of), then yah. Sure the range is short, but a 40mm from an M203 isn't going to punch through what an RPG can. Remeber, HEAP effectiveness is based on warhead diameter.

The RPG has four advantages. Its CHEAP, plentiful, easy to manufacture, and is already battle proven. That being said, rig and improved motor, warhead, guidance, and keep it in the same package so it can be used in existing launchers with an upgraded sighting system, while also being able to use them as increased firepower for your 40mm Metal Storm equipped troopers. You replace your 66mm LAW with an 80mm or better HEAP warhead rocket that works with your existing equipment (less weight, no additional launcher needed).

"40 mike mikes not workin'...toss me a Panzerfaust!"
Click click, FOOOSH, BOOM.

Sorry, been watching too many action movies. :D

Edit:
I added in the 25mm for comparison, in case someone started commenting on using XM-25 technology.

Thanks for the compliment. Its the same as the previous designs, I just attached the Metalstorm tube above the rifle on the reciever mounted rail and figured you could squeeze the electronics into the empty room in the stock and into the scope assembly.

And yes, its a grendel. That tannis blob with the black ovals is a 25 rd mag. Slides in from either side and can be ejected from either side. Feeds like the P90 or the AR180 and ejects out the bottom like both weapons.

I don't know if this would work. But an interesting idea would be to have the cone in a hollow charge warhead expand just before impact. The could be triggered in the same way tandem warhead RPG rounds are, so the triggering mechinism has already been fielded.

Imagine a system that had something like the "tail feathers" of a fighter jet's engines. Just before impact a retaining band would be explosively ruptured allowing a very strong spring to push the cone forward and open it from say 40mm to 120mm while still inside an aerodynamic CF or whatever fairing. This would allow a smaller, more aerodynamic warhead of the same weight to penetrate 3-4x deeper. Working with a 100+mm cone, even the 40mm HC's 2x penetration factor might be able to manage 255mm - 10 inches of penetration. That is sufficient to pierce the side, rear and top armor of all existing MBTs.

Sweet! :D

An RPG is not easier to produce than say an AP 40mm round as it is more complex and larger. Cheap and plentiful yeah, because those are crap surplus that no longer meet the minimum standards of even the most sorry assed army, that's why they are sold for peanuts on the black market. They also perform very poorly, expose the gunner for far too long, and very often fail to go boom or fly straight.

The good ones are NOT cheap, the ammo is very heavy for what you are getting, the ROF is very slow, it is a 2-man weapon if operated correctly, and the launcher is too heavy. I watch movies too, real world movies like the one Bing West made on The Military Channel. During the approach to Baghdad and a few other major cities and then later on the "Thunder Runs" through Baghdad the RPGs were flying through the air like bottle rockets on the 4th of July. They were extremely ineffective and would be rejected for service by most western armies. We have an RPG too and make little use of it because there are better weapons for anything you want to get done.

All rocket type munitions are necessarily heavier as a rocket foregoes the requirement for apparatus (70 ton M1A2 Abrams vs 25lb Javelin ATGM) and its attendant weight and ability to control recoil and instead relies on the constant/sustained thrust of a motor while in-flight to overcome aerodynamic resistance rather than an apparatus which can sustain high pressures and thereby launch a pure projectile at very high speeds with one large release of energy. Both systems have their uses, but if you can afford the weight, amortized across a sufficient number of warheads to be launched, the apparatus-based system will always be more efficient.

As an exercise, calculate the weight of an RPG system with 500 rounds. Compare this to a MK19. You would need a small army to carry 500 RPGs and a Humvee or M-Gator for the MK-19. The max range on the RPG is 1000 meters, max effective about 300 meters. That's pretty crap next to 2,200 and 1,500 respectively. The RPG is an infantry weapon and is popular in the Mid-East so some loser rag-head can parade around and show everybody how big is dick isn't. Any army that is mechanized will use better weapons ...

...which leads me once again to the conclusion that infantry - ALL INFANTRY - should be mounted in Personal assault vehicles using the buddy system just like LE patrol cars do, to make max use of the exhaustively studied, and very well known synergy of two humans working together. By 3 all the synergy is gone - lost to communication overhead and timing/coordination losses. For a number like 8, 11, or 23, forget it. It's a prison bus with a big gun on it.

I wasn't comparing it to a 40mm grenade. I was comparing it to most of the light to medium man portable anti tank weapons currently fielded. What I was saying was that given the diameter of the barrel on the man portable 40mm Metal storm, given the same basic profile of the RPG (slap a seeker head and an improved warhead on it) and use it as a launcher for a light to medium anti tank warhead. Use it to supplement your Gustovs and LAW-66mm weapons, or to at least replace the LAW (instead of having a separate launcher you just muzzle load your LAW rocket into your GL.) if not improve its performance (80mm to 120mm diameter warhead instead of a 66mm warhead).

I know the RPG is crap, but an unguided light anti armor weapon of over 50mm will always find a way to be useful. Case in point, as out dated and woefully underpowered against tanks as it is, the US is still fielding a product improved version of the LAW-66mm

... I was comparing it to most of the light to medium man portable anti tank weapons currently fielded.

Well, for any country that has a GNP within one order of magnitude of the state of California’s, those are ALL ATGMs, and all of those have capabilities so far beyond an RPG I don't see any useful basis for comparison. Putting guidance and a seeker in an RPG makes it a SPIKE mini missile. (If my dad had tits he'd be my mom?) The diameter makes certain performance goals easier to achieve, but in the end it doesn't really matter what the dimensions of the missile are, its weight, range, penetration, ROF, and cost are important parameters - not diameter. Fundamentally, unguided missiles can never have great range because even if aimed perfectly they will quickly diverge from their original aim point.

As soon as you add guidance you can add a LOT of range, and since you will also be adding a lot of expense (this may soon change) you need it to be effective against all but MBTs or you don't have an adequate cost justification to employ the weapon. Therefore, once you DO add guidance you will be driven to add as much range as infantry can use (2-3km before target discrimination becomes a problem) and enough warhead to kill everything up to and including MBTs. (I assume current warhead technology is sophisticated enough to detonate unused motor fuel to good effect, so there may be a range/penetration tradeoff somewhere in the mix.)

In short, I see no real-world tradeoff of RPGs and ATGMs. It is about as useful as discussing what enhancements would be needed to make a P51 Mustang competitive with an F22 Raptor. The end product of such a discussion is to taxi an F22 Raptor up to the ramp and paint “P51” on the nose. To compete with the Raptor the Mustang would have to become a Raptor.

The cost of guidance is not in proportion to complexity. The software is far less demanding to write than say Windows or the software for an F18 Hornet's fly-by-wire system. The electronics are roughly the same level of sophistication as the new iPod that plays videos, so that also is not expensive. The real problem is we'd rather spend 12-15 million on a tank that will never see action because it is part of a US Army package that weights 700,000 tons (and will therefore sit and rust instead of fight) while we fret about light forces firing ATGMs because they are expensive. Well, yes they are expensive - because we don't use enough of them to amortize the development cost. I am hopeful that the SPIKE mini will change this chicken & egg dilemma and we will start using them like lolli pops because then light forces can perform missions that are currently being left undone (Sudan, for one) because there is nothing for the Army but 700,000 tons or stay home.

FWIW, I think political decision makers have finally “gotten it” and it looks to me that between the USMC and SOCOM forces they are eating the Army's lunch, taking its appropriations, usurping its manpower and doing its missions. Hurray! The Army was getting very close to being the club for the enrichment of the retirement status of command. All of their weapons systems are designed to require a stupidly huge number of operators and their command structure is so fat and bloated they can't get out of their own way. Whether this will change or not remains to be seen, but the Marines and SOCOM guys are doing a good job of demonstrating the better alternative.

Note:
This is a bit off topic, but a good place for this speculation anyway. Since tank commander's don't have ESP, and using 1990 vintage visioning systems in the Abrams they were taking the greatest % of thier kill shots in ODS at ranges of 3km and beyond, it seems to me that for launching from light vehicles, be those HumVees, VBLs, or PAVs, the range of ATGMs is a bit short and should be upped to the 4-5km range. The best evidence for this is ITAS equipped Hummers are able to find, surveil and identify targets out to 10km. The Javelin's CLU is almost as capable as ITAS, and could be made so for a modest cost as its daylight optics are its shortcomming, iirc, and that fix is just a bigger piece of glass.

I guess I should rephrase my comment a little. basically what I am saying is put a SPIKE on the end of an RPG style stick so that its compatable with your 40mm metalstorm tube and the electronics already mounted in your advanced sighting system. the other point is, you reduce your personal load by a launcher. you carry your missiles, rifle/launcher, and ammo for the rifle.

If my idea for an *explosively expanded cone could be made to work (or even if not depending on penetration requirements) and the cost of the SPIKE could perhaps be driven even lower due to high volume production, then a shortened SPIKE with a much shorter range - say 300-700 meters - could be fit in the MetalStorm tube and you can leave the stick out of the mix. This was more the direction I was headed with my original comment. It would be great if the SPIKE could have 2-3 different motors of different lengths and weight so the same basic missile could be used without wasting the weight and bulk of long range and having an ability to be fired from many different launch platforms.

I'd have to double check to see who the mfg is on the SPIKE, but if I were in their marketing department I would try very hard to make it the first missile in history to break out of the chicken and egg dilemma by offering the DOD a very low price provided they bought some very large number of them within a certain time frame. If they did NOT buy this volume there would be a kicker at the end of the contract that would represent the difference in per unit costs multiplied by the number of units actually purchased. As the end of the contract approached the DOD would then be choosing between having "some" missiles for a know program cost or a whole lot more for the same $$$.

I think it is very important that these critical assets get built and stored in large numbers in advance, as it would not be possible to make them in sufficient quantities in the critical first few weeks of a major conflict. As both ODS and OIF demonstrated, most of the combat operations will be over, or at least the relative positions of the two parties at a negotiating table will have been decided, within 3-4 weeks. Looking forward this time-frame will only compress further.

* Looking at the details of the existing 40mm shaped charge grenade, it's clear that a pliable or liquid propellant would have to be used as it must reshape itself and fill in behind the new cone shape in short order after the cone is expanded. Something about the consistency of SoftScrub jell seems about right.

Sounds similar to the High Explosive Squash Head (HESH) idea. Of course the hesh flattens a C4 style substance against the armor and then detonates it a fraction of a second later. Perhaps a simple mechanical tip, similar to the Nosler ballistic tip that controls expansion of a bullet after impact would be better than explosively blowing open the cone.

tip of shell hits armor, tip pushes back into mechanism expanding cone and explosive, explosive detonates.

*perhaps coating the back of curved plates and then irsiing them open like a flower and locking in place. that way you could use a more solid explosive.

... is also 40mm and shorter than an RPG. It is also F&F, 20" long, 5lbs, has a 2mile range and costs just $4k. At that range you would need the rifle host's scope - maybe with some fancy tweaks - to operate as a CLU. RPG's are for losers. They have a range not much greater than an M203, far less than an MK-19, terrible ROF, are unguided, and don't have sufficient penetration to defeat much.

Lest I miss my point, my thinking was your design might be able to accomadate a 40mm MetalStorm, NATO 40mm or SPIKE using a space reserved for a 40mm weapon.

http://www.designation-systems.net/dusrm/app4/spike.html

I was reading Daniel Water's site on the M16 development and it was interesting by contrast to the Grendel's development. There were over 200,000 rifles made before they even had bullets with the right powder, the ammo suppliers could not keep the bullets in spec, the few restrictions placed on the weapon and ammo were relaxed again and again so it could be fielded, etc, etc, ect. In stark contrast, EVERYBODY loved the 40mm grenade launchers and the M79 "blooper" was one of the most loved weapons of the Vietnam war.

To my eye this is one of your best designs yet. I like the GL on top, and co-located triggers. As long as the gun is in 6.5 Grendel and doesn't suck the weapon should work well.

PS: Just a reminder, but the penetration of a shaped charge grenade is a multiple of its diameter. This is due to the diameter of the hollow charge's cone. Therefore, even if carrying the same amount of charge, a 25mm is dramatically less effective than a 40mm. IIRC, the multiple is from 3-7x and you can half that for angled surfaces.



I wouldn't say an RPG is Useless. They have roles, just as every weapon does. I think a Carl Gustav is a better choice in general, but ymmv.

I'm not sure about the designs. They look somewhat interesting, but I'm not certain I understand how the rifle ammo fits in, and how it is loaded. Do you have any top or front views?
It looks awefully bulky... A lot like the French PAPOP with the 35mm grenade launcher. I have still not seen any stats on that grenade launcher, but iirc it will be significantly shorter ranged than the US 25mm. That might not be a problem, due to the potential greater power. Also, iirc the French field Eryx, so they are pretty covered on the short ranged targets.

On shaped Charges, it also varies somewhat depending on the standoff. It should be possible to achieve a more optimal standoff in the longer 25mm shell than in the short, stubby 40mm. The cone in the 40mm is also, afaik, nowhere near optimized. IIRC, under laboratory conditions, it is possible for shaped charges to achieve 10x their diameter in penetration. 4-7 is more practical for a fieldable weapon.

It is not necessary for one weapon to do EVERYTHING.

then a shortened SPIKE with a much shorter range - say 300-700 meters - could be fit in the MetalStorm tube

If you are willing to drop to that range bracket, you might as well go with the Medium Velocity 40mm grenade concept. In Nammo's approach, 250g grenade projectiles from the 40x53mm are launched at a reduced velocity of 100m/s (albeit this is higher than conventional 40x46mm velocities). It is credited with a range of 660m versus 400m for the standard 40x46mm. In STK's medium velocity concept, the 180g projectiles from the 40x46mm are launched at the velocity of 100m/s, versus the usual ~75m/s. This is credited with a range of 590m.

(FWIW: The AICW grenade launcher is already credited with a muzzle velocity of 100m/s.)

As for guidance, the US Army Research Laboratory, Georgia Tech Research Institute, and the Defense Advanced Research Projects Agency have been developing a 40mm "Self Correcting Projectile for Infantry Operations" (SCORPION).

snip


As an exercise, calculate the weight of an RPG system with 500 rounds. Compare this to a MK19. You would need a small army to carry 500 RPGs and a Humvee or M-Gator for the MK-19. The max range on the RPG is 1000 meters, max effective about 300 meters. That's pretty crap next to 2,200 and 1,500 respectively. The RPG is an infantry weapon and is popular in the Mid-East so some loser rag-head can parade around and show everybody how big is dick isn't. Any army that is mechanized will use better weapons ...

...which leads me once again to the conclusion that infantry - ALL INFANTRY - should be mounted in Personal assault vehicles using the buddy system just like LE patrol cars do, to make max use of the exhaustively studied, and very well known synergy of two humans working together. By 3 all the synergy is gone - lost to communication overhead and timing/coordination losses. For a number like 8, 11, or 23, forget it. It's a prison bus with a big gun on it.



There is SO much difference in explosive and penetrative power between an RPG and a Mark 19 that it isn't even funny.

The Mark 19 is really and area fire anti-personnel system, with limited anti-vehicular capabilities.

The RPG is an anti-tank system primarily. YES the Iraquis had shitty RPG rounds. A lot of the "ineffective" rounds were also ANTI-PERSONNEL rounds, which iirc have about 2 times the effective range of the anti-tank rounds. They also probably have the explosive/fragmentation effect of 3 40mm grenades.
The Russians and Ukrainians, iirc both make rounds for the RPG that will penetrate over 500mm of steel, and don't have the fuses that are very subject to failure. Even The old ones, when they go off, will still penetrate around 300mm, iirc. This will penetrate an Abrams from the side or rear, at least in a lot of spots.

For your given weight of a Mk19 and ammo, I would rather have an actual cannon. Less capability for indirect fire, but a lot easier to hit with. I'd say 23mm Russian or 30x113 nato. MUCH better for hitting bunkers.


Now, I am VERY curious about the FN "High Impulse Weapon system" The first version, iirc was a 76mm grenade launcher, the more recent one uses 40mm HV, as in the Mk 19. SUpposedly point and shoot out to 300meters.

I have been interested in the idea of a light recoilless rifle, and suspect that it would be relatively easy to build one the would use a blow out cartridge case on a 60mm mortar round. Particularly given the capabilities of the RUAG round, it would make a SUPERB anti-personnel/anti-vehicle round.

If you are willing to drop to that range bracket, you might as well go with the Medium Velocity 40mm grenade concept. In Nammo's approach, 250g grenade projectiles from the 40x53mm are launched at a reduced velocity of 100m/s (albeit this is higher than conventional 40x46mm velocities). It is credited with a range of 660m versus 400m for the standard 40x46mm. In STK's medium velocity concept, the 180g projectiles from the 40x46mm are launched at the velocity of 100m/s, versus the usual ~75m/s. This is credited with a range of 590m.

(FWIW: The AICW grenade launcher is already credited with a muzzle velocity of 100m/s.)

As for guidance, the US Army Research Laboratory, Georgia Tech Research Institute, and the Defense Advanced Research Projects Agency have been developing a 40mm "Self Correcting Projectile for Infantry Operations" (SCORPION).



IF a shorter range is acceptable, I'd rather put a bigger warhead on Spike.

I believe the xm25 grenade is faster than 100mps, I thought it was about 160mps. I can't seem to find the actual figures anywhere. I saw them once, perhaps on DTIC?

i dont ususaly post on this thread but i would like to point out a couple of things about the rpg.

pros
as a concept the rpg is extreamly flexable and rugged. it is very simple with few moving parts for soldiers to mess up. it is flexable - you can use it for long range anti personel, or as a short range anti tank weapon. it's warhead isn't limited to the diameter of a launch tube. there for new rounds can be developed to change w/ technology/

cons
it is heavy, and difficult to aim unless used by an experienced operator.

the rpg is a 30 year old platform. im sure that many of these faults could be fixed with new technology. i wonder what could be done with the same concept but w/ newer materials/manufacturing and a better sighting system.
imagine a carbon fiber wrapped launch tube and a reflex type sight with a more wind stable warhead.

many very effective military orgainzations have used this weapon to great effect over the past 30 years. some examples would be the isrealis who also currently manufature their own line of rpg 7 rounds one of which is lazer guided, the chechens, who, whatever you think of them used rpgs to make grozny a living hell for the russians during the 1st and 2nd invasions,
and lets not forget that in somolia, iraq, and afghanistan the rpg has been used effectively in several anti helicopter ambushes.

american solders and marines have commented that they wished that a similar weapon was in the u.s. inventory.

hmmm. personally i would take a modernized rpg anyday over a mk 19. especially sence most fighting is in cities these days in places where the vaunted PAV couldnt really get to (ie on top of buildings, in rooms, around rubble.)

Okay, quick primer on the AAAR1 (my AR design that I have been kicking around on the thread for ...forever it seems).
The basic layout is similar to the FN P90, but with a few notable differences. The operation system is a two lug gas operated rotating bolt, similar to the M1/mini14/m14 family of weapons (and as I found out a bit like the AK in certain respects). The magazine slides into a bracket going over the top ofthe gun. On top of this bracket is the primary sight rail. Magazines contain 25 rounds in a 45 to 60 degree off barrel axis configuration till it reaches the loading end where it does something similar to the FN p90 mags and aligns the rounds with the bore. The magazine can be slid in from either side and ejected from either side, with the following magazine able to help "push it out" in the event of it sticking. once fired or manually cycled by the ambidexterous charging handles (which would also double as a bolt assist device when locked in place) the cases or cartridges eject out the bottom of the rifle, behind the pistol grip (again, similar to the P90). Current chambering is of course 6.5 grendel with possible chamberings in .40x39 and .50 beowulf running around in my noggin. Latest iteration posted has a 40mm metal storm tube attached to the top rail as a "proof of concept" type sketch of how the unit would attach to the rifle (similar to how they did it with the AUG to make the AICW)

I hope this clarifys things a little better till I can get around to labeling my illustrations

http://www.globalsecurity.org/military/library/policy/army/accp/in0546/lsn2.htm#parta
http://www.inetres.com/gp/military/infantry/antiarmor/M20.html
http://www.inetres.com/gp/military/infantry/antiarmor/AT4.html
http://www.hkdefense.us/pages/military-le/special%20applications/gmg.html
http://www.military.com/soldiertech/0,14632,Soldiertech_MGL,,00.html?ESRC=soldiertech.nl

The RPG is an infantry weapon and therefore in MOUT it is much more effective - provided you aren't faced with the use of heavy armor or massed long-range firepower. In cases like the fight for Fallujah in Nov of '04, where we used a lot of armor and accepted the consequential destruction of property,, you will not be able to get in close enough to engage at effective ranges because Bushmaster cannons and MBT HE rounds and possibly arty, CAS and AC-130s at night will use their range to kill you at arms length. That's not to say some will not get in lucky shots, but looked at from the prospective of command, their losses will be 10x or more than yours.

Since the RPG is an infantry weapon it should be compared only against other infantry weapons. The M79/M203 weights 1/8th as much and its ammo weights 1/10th as much and will match the RPG's effective range in MOUT. RPG gunners are therefore required to survive both grenade and rifle fire and must maneuver constantly to avoid counterbattery fire. This makes the transportation of 5lb warheads and a 17lb launcher with significant number of warheads unlikely in sustained combat where positions that offer cover are soon discovered, monitored and engaged in a persistent manner.

To answer my question, 500 rounds weights 2,500 lbs, and this for a weapon that has a 50% hit probability in winds as low as 7 knots at 180 yards and 25% if you have a bit of chain link fence handy. This is the same weight as a MK19 with tripod and about 4,700 rounds which can be fired at 5 times the effective range. A HellHound version about doubles the penetration to about 100mm (4 inches). Since this is not an infantry weapon to be used when maneuver is required it will be mounted on some mech platform negating the need for the 44lb tripod. (add another 90 grenades to the count) An RPG round weights 10 X that of a 40mm grenade and yet is no more likely to knock out something like an uparmored Hummer or PAV.

I am assuming the SPIKE and Javelin will track a target if it moves after launch, which no RPG will do no matter how close the range. This makes a SPIKE attack on light armored vehicles MUCH more effective than an RPG and makes a short range version worth considering. (The Marines do have an RPG and have had it for a very long time. They don't use it very often because for mech infantry it is near the bottom of the list as a weapon choice.)

The 40mm HellHound has about the same strength warhead as an anti-personell RPG round and I am assuming it can be adapted to the much simpler full-strength MK-19 round. While it is true that it will not penetrate as well, the penetration it does have will penetrate most light armor and it is therefore equally effective against most threats. What it will do is saturate an area at great range, clear building at great range and do so in most cases without collasping the structure into rubble fortifications. A weapon with the ROF of the MK-19 and penetration of an anti-tank RPG would collaspe buildings into rubble fortifications and StarShip and PAV operators would have to use discrescion in using something as heavy as an RMK - which in its heaviest RMK-35-350 version is at least 3x the power of the Bradley's Bushmaster cannon.

A MK19 will also quickly kill or suppress large areas so would-be RPG gunners end up dead or on the run at critical moments when you need to advance or maneuver. In spite of the theoretical posibility of an RPG penetrating thick armor like an Abrams it has seldom been done - and this is with RPG gunners being suppressed by one on-tank .50BMG, one M240 and infantry. Retask the escort foot infantry into PAV platforms and they will have much greater anti-personnel firepower than the Abrams or Bradley and would make such shots nearly impossible. Beyond this simple slat armor has proven effective, more effective than ERA, and beyond that the British Electric Armor will deal with all SC weapons at a weight within the scope of the PAV - although I am not a fan of such a special purpose defensive system.

By contrast to foot infantry, a lowley M-Gator can travel 3x as fast, much further before needing a rest or replenishment, and can carry much more effective area-defense, anti-armor and anti-personell weapons than anything a similar number of infantry can carry. If you want to kill armor there are MUCH better weapons available, provided you don't have to carry them on your back.

Since it is at this point a purely theoretical platform we can't really know, but I believe the PAV would be quite good at breeching rubble fortifications as it has great ground clearance, its V-hull can cut through or clear rubble, and even with its wheels locked its suspension can crawl over rubble. The PAV is most vulnerable when it cannot hide and must fight toe-to-toe. This makes it much more vulnerable in MOUT. To compensate I designed the StarShip to be able to get up into 2nd and 3rd story windows and over 1st and 2nd story rooftops. In the sandbox this accounts for about 90% of all structures. A few 2,000 lb bombs as part of prepratory bombardment will take care of the rest. For near-peer conflicts fighting in built-up areas it would be better to just level the city and fight through the rubble so all of the action is happening close to ground level. Rubble fortifications are great as long as you don't need to maneuver with heavy weapons as you will have to carry them on foot. This limits the speed of maneuver to crippling levels and I would expect PAVs to simply blow through defenses by using area-denial weapons to pin heavy weapons in place until they have passed by them - most likely engaging and destroying them in the process. With PAVs we should then be able to engage infantry with STANAG level III or IV+armored assault vehicles. This allows us to retain the use of heavy, long-range weapons on fast, maneuverable platforms that offer their crews good protection.

The PAV's and StarShips must fight in packs to cover each other, and something like the RMK would be a very good and potent fit for the StarShip, keep the backblast up away from friendly forces (unlike the muzzle blast from a Bushmaster or M1A2 main gun). The key to the PAV's sucess in MOUT is that they be fought in large numbers and well coordinated. In the process they can make CAS operations much safer by supressing rooftop threats at great range.

Blackstar,

We do have an RPG.

They only want them until they have to hump them, then they want a ride on an armored vehicle.

If you modernize an RPG the first problem you have to address is hitting the target, not penetration. Penetration of 330mm is no more effective against most light armor than 100mm because no Toyota truck, Jeep, or even the standard M113 can stand up to this threat. Hitting the target is the problem the SPIKE is correctly focused on.

On a dead calm day with a stationary target, no near-ground thermals, infinite time to aim, perfectly aligned and calibrated munitions, a perfect launcher, a trained gunner, no one shooting at him or blasting his area with grenades, the target doesn't move when it sees his launch blast, and it doesn't have some chainlink fence, ERA, or slat armor it is very likely to hit the target. With a practical launch rate of 2RPM, in the same time it takes him to line up another shot I can put 175 grenades into his general area PER Hummer, PAV, Bradley, AAV, ect.

RPGs are for third-world, foot-bound losers. They aren't fighting us with RPGs, they are fighting us with IEDs because RPGs failed miserabally for them. If Les Aspin hadn't had his head up his ass, and we'd had AC-130 gunships in Somalia, no one would have cared what the ragheads had. We would have leveled every building within 300 yards of the Vacarro Market and the streets would have been as empty as a jug of whiskey at an Irish funeral. Ditto for M113 Assault Cav tracks with 1 .50BMG and 2 M60/M240s each, or PAVs. http://www.ktroop.com/m113.htm
http://www.defenselink.mil/specials/secdef_histories/bios/aspin.htm

You don't need to drive a PAV into a room to clear the room/s. You just need to punch through windows and walls and kill everyone in the room with grenades or direct fire assets. The room is just fine. It's a passive structure with neither mallice nor benevolence. It's the occupiers of the room that need engaging and that can be done without driving your vehicle inside of it.

The Paki wheeled armored vehicles that rescued the 10th Mountain were MUCH more poorly armored than a PAV, Stryker or LAV - yet they got the job done very effectively. The PAV can offer such great ballistic protection in a lightweight vehicle for 3 reasons. First, becaue it uses 45 degree angled surfaces any thickness of armor is about 230% as effective as that of the flat surfaces of the Stryker, Abrams, Bradley or HumVee. Second, the crew area that is most heavily armored is very small and pointed as well as V-hulled. Third, it uses the best mix of metal and ceramic/composite materials which offer a 3:1 weight advantage. Taking the 3:1 weight advantage and combining it with 230% effectivenes due to geometries we get 690% of the ballistic AND mine protection for the same exact weight as box-based designs. For mine protection it can loft the crew compartment 40" above ground level where the mine's cone of destruction is 1/1000th as powerful as it is at ground level. The PAV is not designed with smoke and mirrors or magic, it's just algebra.

http://www.strategypage.com/fyeo/howtomakewar/default.asp?target=htweap

... interesting...


August 31, 2005: The U.S. Army is working on a 40mm grenade that will "self correct" its trajectory using puffs of air when launched, providing greater accuracy for urban combat. Currently, the M203 grenade launcher is accurate out to some 150 meters, for a point target like a window. The SCORPION (Self-Correction Projectile for Infantry Operations) program is hoping to increase grenade accuracy to around 250 meters.

The system would consist of a "smart" 40mm grenade with a tiny jet on one side of the projectile to provide bursts of air for guidance corrections as errors are introduced by wind or other factors and a bolt-on device that would automatically upload range, muzzle velocity, and quadrant elevation of the launcher to the grenade. Once launched, it senses its trajectory using a magnetometer and several other sensors that measure deviations from a perfect launch arc, with the jet providing in-flight adjustments. Developers are hoping to use something similar to the ballistic computer system developed for the OICW to provide the initial ballistic data to the round. The Army Research Laboratory expects to complete the program by September 2006. – Doug Mohney

.. is still a PAV.

My B-Day / NYE party was interesting... in part because there were some special forces types there. One, in a position to know, reports that a most unlikely branch of the DOD is building a V-hulled light assault vehicle. Is it a PAV? ... the world wonders... :cool: The PAV thread has gotten nearly 5,000 views, more than any other excepting this one as far as I can tell.

back to the topic at hand, I'm not looking to replace or make the PAV obsolete, I'm trying to give our guys and girls a rifle that can be packed as backup in the event they have to go in a building or thier PAV is disabled and they have to go in on foot (or that would be used by SF types, since PAV's are rather large for what they do).
basically I tried to squeeze a 6.5 gren into the smallest package possible. You can always make an AR bigger (longer barrel, larger sights, more elaborate stock, bigger magazine, etc.) but making it smaller is very hard.
hence the reason I used an abbreviated bullpup design based off a known reliable action with some modernized improvements, feeding from the top and ejecting out the bottom. it gives the best mix of short length, balance, and ambitexterity.

Some time ago, I thought about placing the magazine inside the pistolgrip, but wrote that off as a bad idea due to the difficulty of wrapping your thumb around the pistol-grip in a pleasant grip...

A few days ago, I remembered this, but at the same time questioned the need for the thumb to be wrapped around the pistolgrip... Is it really necessary? I have talked to shoters who say their accuracy is improved if they fire "thumbs up" in stead of around...

Of course, you cant solve one problem without encountering a new... Now the thumb may be in the way of the ejection-port... The obvious way to fix this is to make sure the pistolgrip is placed sufficiently far down to let the tumb stay out of harms way...

Another problem would of course be where to place the safety...
To keep things extremely simple, I would opt for a combination of the Steyr AUG-trigger, and the Glock trigger, where there would be a safety-lever on the trigger itself, and the amount of pull on the trigger would indicate single-shot or full automatic... In addition, a transport-safety should be added, to make sure it is not fired unintentionally...

This would make a very compact weapon, with very short reaction time, and sufficient barrel-length, making it ideal for CQB and FIBUA, as well as for longer ranges. Though it may be a bit radical for many people, as they would not feel very safe without an ortodox safety-lever...

Well, it seems like my last idea either was perfect, and nobody had anything to add, or it just didnt catch any interest... :)

Anyway, I remember when carrying my G3 rifle unslinged, (as I did most of the time) I carried it by simply wrapping my fingers around the front of the mag and magwell. It was actually a quite pleasant grip, and it was just underneath the CG of the rifle.

To describe the design as "UZI-like" was the first thing which struck me, but it is actually more like a "lengthened" bullpup-rifle with the pistolgrip integrated in the magwell.

This way you could actually get an ambidextrous "bullpup", without any of the traditional shortcomings of a bullpup or a orthodox rifle...

I actually made a hand-drawing of how I envisioned this rifle, and IMO it looked like something straight out of Star Wars...

Look for yourselves:

http://i32.photobucket.com/albums/d19/dobrodan/drawing2.jpg

Hey, I used to carry my HK-91 around the "ranch" like that...glad to know its common.

For a weapon that would always be shouldered, yes, I agree that it would be a good position. The only problem I see is that there are some "unshouldered" positions that would make this design unpalitable for combat rifles. Might make a good hunting rifle though. Not much shooting from the hip or around corners when you are hunting deer.

Interesting design though..I would recommend persuing it. Actually it might make a good revamp of the XM25 GL once they combine it with the lower rifle module after they get the weight down.

On another note the SCAR L got a review in "Special Weapons for military & police". If it lives up to the hype and what SOCOM wants out of it, I will be impressed. I also like what they have done with the EGLM. I was envisioning something like that EGLM on the basic (read "non-grenader") config for the design I was working on. Admittedly it changes the balance, but if you adust the center of gravity of of the rifle back far enough (like the Russian Groza rifle) the addition of the GL puts the balance at the pistol grip, or maybe just a little forward of it, maybe behind it...depending on which is ergonomically correct (again, like the Groza with its 40mm caseless GL system).

The Groza was designed from the outset with the GL attachement in mind, same with one of the other bullpup designs that Russia has put out. Its a perminant part of the gun...of course this is made possible in both cases because the grenades are basically 40mm single pulse rockets. Not sure how effective they are, but its the standard GL for the Russian military.

Anyway, I will be talking with a guy I know about building a prototype in the near future of my AR design. Let you all know how that turns out.

http://www.strategypage.com/fyeo/howtomakewar/default.asp?target=htweap

... interesting...


August 31, 2005: The U.S. Army is working on a 40mm grenade that will "self correct" its trajectory using puffs of air when launched, providing greater accuracy for urban combat. Currently, the M203 grenade launcher is accurate out to some 150 meters, for a point target like a window. The SCORPION (Self-Correction Projectile for Infantry Operations) program is hoping to increase grenade accuracy to around 250 meters.

The system would consist of a "smart" 40mm grenade with a tiny jet on one side of the projectile to provide bursts of air for guidance corrections as errors are introduced by wind or other factors and a bolt-on device that would automatically upload range, muzzle velocity, and quadrant elevation of the launcher to the grenade. Once launched, it senses its trajectory using a magnetometer and several other sensors that measure deviations from a perfect launch arc, with the jet providing in-flight adjustments. Developers are hoping to use something similar to the ballistic computer system developed for the OICW to provide the initial ballistic data to the round. The Army Research Laboratory expects to complete the program by September 2006. – Doug Mohney



I suspect it would be a lot cheaper to just increase the basic accuracy of the grenades. oh well.

Some time ago, I thought about placing the magazine inside the pistolgrip, but wrote that off as a bad idea due to the difficulty of wrapping your thumb around the pistol-grip in a pleasant grip...

A few days ago, I remembered this, but at the same time questioned the need for the thumb to be wrapped around the pistolgrip... Is it really necessary? I have talked to shoters who say their accuracy is improved if they fire "thumbs up" in stead of around...

Of course, you cant solve one problem without encountering a new... Now the thumb may be in the way of the ejection-port... The obvious way to fix this is to make sure the pistolgrip is placed sufficiently far down to let the tumb stay out of harms way...

Another problem would of course be where to place the safety...
To keep things extremely simple, I would opt for a combination of the Steyr AUG-trigger, and the Glock trigger, where there would be a safety-lever on the trigger itself, and the amount of pull on the trigger would indicate single-shot or full automatic... In addition, a transport-safety should be added, to make sure it is not fired unintentionally...

This would make a very compact weapon, with very short reaction time, and sufficient barrel-length, making it ideal for CQB and FIBUA, as well as for longer ranges. Though it may be a bit radical for many people, as they would not feel very safe without an ortodox safety-lever...


Firing Thumbs up on a conventional rifle like an M-14 on a rifle range is one thing.

I don't think combat usage of a pistol gripped assault rifle (or even a conventional rifle) would be very practical with "thumbs up."


I don't really like the Glock trigger setup. It works, but...

I'd rather go with a grip safety and a transport safety.

I agree on the glock trigger...a 1911 style grip saftey would be better in my opinion as well. I do however agree that the AUG style "select fire trigger" would be a good idea, especially with a nice, sedate firing rate (panicked people tend to hold down triggers...even soldiers). If you want to ensure single shot, add a "block" to keep it from firing full auto, so that you have a safe, single, and single-auto trigger pull selection. I personally think that the P90 style saftey would be good for this...unless you just HAVE to have a thumb safty and then going with one similar to the SCAR-L/H family would work too.

For a weapon that would always be shouldered, yes, I agree that it would be a good position. The only problem I see is that there are some "unshouldered" positions that would make this design unpalitable for combat rifles. Might make a good hunting rifle though. Not much shooting from the hip or around corners when you are hunting deer.


If you add a "thumb-support" on each side of the grip, you should be able to have a firm enough grip to allow you to fire one armed on full-auto...

Actually, a grip-safety could be added on this thumb-support, even though it should be able to be bypassed, in case you have hurt your thumb...

I do however agree that the AUG style "select fire trigger" would be a good idea, especially with a nice, sedate firing rate (panicked people tend to hold down triggers...even soldiers). If you want to ensure single shot, add a "block" to keep it from firing full auto, so that you have a safe, single, and single-auto trigger pull selection. I personally think that the P90 style saftey would be good for this...unless you just HAVE to have a thumb safty and then going with one similar to the SCAR-L/H family would work too.

The P90 safety is as I have understood a "side-to-side" safety? I am no big fan of those... That is similar to what we have on the MG-3, and the only thing I used that safety for was to make sure the MG was cocked, for barrel-changes, and when emptying the weapon, leaving it open for inspection...

However, If seasoned soldiers hold down the trigger in panic, I believe the reason to panic is very understandable.

What I have understood of Austrian and Australian soldiers is that they like this trigger-selector very well. After you get used to it, it is no problem to use after all...
However, the traditional marksman-techniques being taught in other armies is not appliable to this trigger, which is some of the problem when for example British soldiers has a chance to test the AUG on the ranges, and unwillingly empties the whole mag in 2 seconds...

Thats why I like the P90 saftey in addition to the selector trigger. If I recall correctly, the trigger has a pin that sticks down into the safty "drum" (its not a push through, its a rotate type saftey). With the selector on safe, it allows no trigger movement, with the selecter on 1 it allows it to move back to the first position allowing single shots. In the full auto position it still allows single shots but also allows you to pull it all the way back in to full auto mode (like the AUG).

Its ambidexterous without being overly complicated, its indexed with the trigger finger, and outside the trigger guard, its out of the way of gloved hands, can be manipulated by said gloved hands, and works kinda like turning a faucet. Rotate right for more bullets, rotate left to shut off bullets. :D

Quite intuitive once you get five minutes to familiarize yourself with it.

http://www.dentrinity.com/News/maruip90/p90lower.jpg

This was the best pic I could find (airsoft)...

What I (theoretically) dislike about this design is that you either need to twist your hand to react the selector with your thumb, or reach trough the hole with your index-finger... It may be a (little) bit time-consuming to operate, but would probably function extremely well as a selector/transport safety, with either a trigger- or thumb-safety as a main-safety in the ready-position.

I have no idea how you would manipulate one of those with the thumb. The saftey is intended to be operated from either side by the index/trigger finger. The thing right above it is the trigger itself. Again, rotating it counter clockwise moves it towards safe, while rotating it clockwise moves it towards auto. And it can be operated from either the left or right side (though the lefties finger motion is the opposite of the righties finger motion because of the direction of turn on the pivot point). My suggestion is to find an airsoft store that carries the P90, and try it out. Its harder to explain than it is to actually pick one up and manipulate it. I find it a hell of alot more comfortable than the AR15 selector or an HK G3 style saftey (grew up shooting an HK91.)

Also, because its rotational, it solves the problem usually associated with crossbar type safties (like on my Remington 870).

Ah! I see! It is simply a rotating disk! Clever!

However, IMO It would probably work best as a secondary safety in combination with trigger or thumb-safety...

I would personally go with thumb saftey though trigger saftey might be more appropriate. One thing I have noted over the years of shooting 1911's is that if you don't hold it Juuuuuust right, a touchy one will fail to fire because you don't have the grip saftey down. There are situations where you might not be able to get a propper grip on your weapon (plus it also would preclude the use of different pistol grips).
Now that I think about it, maybe a trigger saftey would be a good idea...just not Glocks. Something similar to the Steyr M series pistols. Not only does it provied a good passive saftey, but it also acts as a "loaded chamber" indicator. In the dark this could be very helpful.

Maybe I'll implement something like that on an A1 or A2 variant of my design. Right now I am in the "KISS" mode on designing it. Additional safteys can be implemented LATER.

With "thumb-safety" I didnt mean a classic selector, but a lever or button that need to be depressed to activate the trigger...

I am trying to design the magazine for my IAR design. Does anyone know the approximate ratio of compressed spring to ammunition? I'm guessing about 1/3 the length of a full magazine is spring and follower, but I haven't really researched it all that well. Any information would be helpful.

I found a picture of an OICW-style weapon with "my" magazine solution:

http://images15.fotki.com/v259/photos/2/262472/1782896/shotshowwedjjpeg-vi.jpg

I am not sure which country it origins from, but I suspect France or Italy based on the DPM...

While an interesting attempt, I am sorry to say the designers should be sacked... It shows a near total lack of ergonomics, and appears much too big and bulky. Absolutely not very user-friendly... Hopefully, it is just a mock-up...

Its a PAPOV. Its french, its got a 35mm top barrel and a 5.56 bottom.
Please refresh my memory, what was "your" magazine idea? Unfortunately I have slept since then

I am trying to design the magazine for my IAR design. Does anyone know the approximate ratio of compressed spring to ammunition? I'm guessing about 1/3 the length of a full magazine is spring and follower, but I haven't really researched it all that well. Any information would be helpful.

I believe the follower is squeezed all the way to the bottom, thereby hiding the spring inside it... The spring itself does not build very much...

Anyway, I thought of a "telescoping" magazine, where you actually have a "conventional" magazine in the bottom, with a follower and spring, but without feeding-lips, sliding inside another magazine... To enable the telescope to retract, an elastic strap is used to force the bottom part into the upper...

This does however mean that a few problems may arise:

-Elastics tends to get brittle after being exposed to sunshine or becoming old.
-Elastic tend to lose its strengthy when being suspended over a long period of time.
-It might be vulnerable to freezing or dirt entering the magazine

Its a PAPOV. Its french, its got a 35mm top barrel and a 5.56 bottom.
Please refresh my memory, what was "your" magazine idea? Unfortunately I have slept since then

The "UZI-style" magazine in the handgrip...

actually what they did was put the pistol grip off to the side, similar to what you described but more like a remote firing grip on something like the XM307 or a minigun.

You are right though...the designer needs to be shot...with the 35mm portion preferably :D

One of the traditional complaints about bullpup rifles is that the center of gravity is moved significantly to the rear, unbalancing the load somewhat. I personally have found it quite comfortable to shoot, but having the balance closer to the shooting hand grip would be preferable. One way to balance this out is to use a longer barrel and bipod (DMR/SAW) thereby increasing the weight up front. While this may be preferable for your DM or your SAW gunner, most of your troopers will want something a little shorter. Next option is to make everyone not a SAW/DMR carrier a grenadier…except that eventually our XM320s or FN EGLMs are going to be replaced by either an over the top metal storm or the XM25 OICW derivative. Those would be too costly to put in the hands of every soldier (at least right away).

Then there is the Masterkey/”Ripley” idea (mount a short shotgun under your AR barrel), which is somewhat popular because of the utility and variety of ammunition available for the 12 gauge Shotgun. The traditional Masterkey has the issue of too long a pull and an inconvenient trigger location, as well as excessive weight, which is why C-more systems came up with the LSS straight pull bolt action. As much as I like it the LSS (as it solves most of the issues associated with the “masterkey”) it also has an issue with the box magazine sticking out so low.

It did cause me to hit on and idea though.

The S. Africans have over the years come up with a variety of very handy shotgun packages (not to mention the rotary GL concept based off the same systems). While I like the rotary systems (Striker/Protecta/MGL) they have the weight issues due to the huge, under slung “cylinder” for the 12 shot (6 shot on the 40mm) capacity. While the size of the cylinders could be reduced (reduce your ammo to 6 12 gauge or 3 40mm), it still would not solve the weight issue.

What I finally came up with, is a derivative of the Neostead shotgun. The overall design is a bullpup, reverse pump, dual tube fed shotgun. Each tube holds 6 shots and can be tipped up to be reloaded (tubes on top, mechanism underneath, ejection from the bottom). The under barrel system I envisioned would mount the breach block end of the gun (the breach block does not move, the barrel moves, which is why you pump forward instead of aft) next to the trigger guard of your rifle, and be hooked into the bullpup trigger bar, allowing you to fire it from the same trigger, or have a second trigger (like on the FN EGLM) just below the rifle trigger. The tubes could either be tipped to the side for reloading, or use a more conventional fixed tube (one on each side of the unit) and gate load system (just like almost every lever action out there). With this configuration your AR fits in the area that is usually just “empty space” in your shotgun stock, with the barrel running over the top of your shotgun. Scale it up a little and you could even use the lower impulse 25mm rounds designed for the XM25, with possibly 2 shots on each side for a total of 4 (or in the 12 gauge configuration 6 12s total).

Anyway, I’m just posting this to see what ya’ll think.

One could also mount a spring on the gun and use a non-elastic nylon strap that is wound into a spool on the gun. The spring & spool would be a variation on a window shade's winding mechinism. With a nylon spade at the end one could pull the strap all the way out, unclip the end, change mags, and clip the strap end back in. It might also be possilbe to fashion the mag so the strap end automatically clips itself in when the mag is inserted. It would slow clip changes down a bit, but should prevent clips from falling out and a much heavier spring tension could be used. A tape measure mechinism works the same way come to think of it.

Humm.. the position of the strap end would give a pretty good indication of remaining ammo too. It would also allow for VERY, VERY long/large clips. Perhaps 200+ rounds.

Let me see if I understand your idea here, instead of using a spring in the mag, pushing a follower which in turn pushes the cartridges to the feed lips, the follower is thin/flat and the springs/elastic are on the outside of the magazine and they "pull" the follower which in turns presents the ammo. An theoretically the follower could be pulled out and the magazine loaded from the "Back" end.
Had an idea like that a while back, and just hadn't persued it....I like it cause it "fills" the magazine instead of leaving that dead space for the follwer and spring coil. I had another idea that did away with springs all together in which the cycling mechanism indexed the next round (ratcheting system so that you could pull a partially loaded mag and then reuse it without screwing up the ammo stack). I haven't persued that on either, but it packs more ammo into the same amount of space. Would make the 50 rd "P90" style top mount magazine feasible. Once I get a prototype working with spring loaded magazines, I may pursue that next...or use someone elses design if they'll let me :D

Cool,
Yeah, you have the general idea there.

The F.A.B. belt tensioning system is a sprung version of the unsprung mechinism that advances the film in a 35mm camera - with its 35mm feed pawls. (Your garage door spring works the same way) It's 4:00 in the morning here and I have just designed this thing tossing and turning in my "sleep". I'm putting the triple O-ring sealed spring mechinism on the gun itself and have figured out a kick-ass way to connect the spring-loaded pawls to the belt. Two hundred round mags are child's play with this - and no spring to go bad in the mag and zero tension to have to load the mag against! Not that the spring needs to be that strong but the belt could easily have a thousand lb breaking strength and is part of the mag, perhaps a plastic, disposable mag. This thing is just damned slick! If you want to use it let me know and I'll send you an NDA and then the engineering diagrams.

Oh, and just for reference, I have decided on a swappable upper reciever, independant of the barrel trunion and the rest of the mechanism so that you can use either a conventional mag, "90 degree" turn mag, or belt feed upper. Still trying to think of a way to allow a mag well/feed port for using conventional magazines while having the "90 degree" in the same upper (so that you can use someone else's mags in a pinch). I was thinking something similar to the angled feed for the AR15 mags in a SAW, but it will be sticking out at an angle (either up to the right or left)...though that might make it easier for a cogunner to slap in a beta on the opposide side from the gunner...hmmm, that has potential.

Forgive me for the possible thread drift, but lately I've been thinking a lot around this topic. I understand the benefits of a front-locking rotary bolt, but the MBTS and MBTF for the M240 are phenomenal.

Has anyone considered building an assault rifle around a selective fire version of that action?

It seems like you could minimise the weight by building it around a trunion with rearward extentions to support the locking shoulder. It would be probably heavier than an AR, AK or Garand action, but it might be worth it - especially if you were developing a Stoner-style system or family of weapons...

E,

Well, this thread has drifted all over the place so many times its proper name might be "Drift" :D

I like your idea a lot - build on success. Perhaps you could start a new thread here or in the Military section and start with an exploded diagram of the M240's action as I am not familiar with it and would like to follow along and perhaps contribute to the discussion. My understanding is it is a BAR action turned upside down - if that helps you. I don't know either action so it doesn't help me.

Part of my interest in this is I have some good metals calculators and some industry contacts to be able to mold things like Ti as though it were plastic so we might be able to do a fun project and really nail down a nice Grendel MMG or GPMG - perhaps optimized to feed Lapua 144 with slight adjustments to the barrel throat and feed mechanism. I think it would make a very nice project if you are game.

I have also been thinking about a new belt system made of flat rectangular high temp "plastic" or aluminum links with perforrations along each side of a solid base that grasps/holds/retains the bullet and a continious strip of clear plastic "bubble pac" upper that is seated into the linked base plates with something like the small rubber hose that holds the screen in place in a modern screen door or window screen. (the kind you press in with what looks like a pizza knife)

The feed mechinism (or co-gunner) would then peel the slightly greasy upper protective film off as the belt is being fed. This keeps the bullets hermetically sealed and completely free of FOD until a split second before being fired. Such a belt should be able to be wound into a sturdy but light ABS plastic case and make for a very user-friendly 2-500 round backpackable package with about a 2.5" width. For vehicle mounting 2-3 such cases in the standard right-side mount would provide up to 1,500 ready rounds - not that such a thing would be tailor-made for a PAV or anything... ;)

And now for something completely different...

A rising chamber, differential recoil, automatic weapon design from KAC. (Could it be their failed LMGA design proposal for General Dynamics?)

US Patent Application #20050262750: "Auto-loading firearm mechanisms and methods" (http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220050262750%22.PGNR.&OS=DN/20050262750&RS=DN/20050262750)

I love fierarms patents :)

Here is some info on the FN MAG58/M240: LINK (http://www.globalsecurity.org/military/library/policy/army/fm/3-22-68/c03.htm)

Here is a photo of the action. If you are familiar with the BAR action, you can see it is an "upside down" version:

http://www.globalsecurity.org/military/library/policy/army/fm/3-22-68/image870.gif

The locking shoulder is in the "hole" below and behind the bolt when it is locked. MRBS was almost 3,000 and MRBF was over 6000 when the Brits tested it against the M60...

Frequent military transfers have taught me to respect experience, corporate knowledge, and the cohesion of established groups and organizations. I've always made a habit of acquainting myself with the capabilities and ideas of others rather than blundering into hasty judgments, criticism, or proposals. After reading this thread and others over the span of several weeks (admittedly with countless side-trips--courtesy of the fantastic variety of links provided herein), asking, and receiving great answers to, a few ammunition-related questions, I'd like to join the discussion here, as small-arms design (and, of course, small-arms employment) is my primary area of interest. Essayons wrote:

"Forgive me for the possible thread drift, but lately I've been thinking a lot around this topic. I understand the benefits of a front-locking rotary bolt, but the MBTS and MBTF for the M240 are phenomenal. Has anyone considered building an assault rifle around a selective fire version of that action?"

"Forgive"? This is one of the least-drifting posts I've read on this thread. I'd prefer to congratulate and to thank you from the bottom of my heart for such an on-topic question. Only your insights and those of a few other dedicated rifle-engineering enthusiasts have borne me up through forty-one meandering pages; it seems as though every time anyone mentions the prospect of mounting a grenade launcher on a certain rifle, three pages digressing from launcher vs. hand grenades, to whether rockets or mortars are better (or helicopters or artillery), to how many grams of pentanitrated superwhamathol can dance on the head of a .22 bullet, invariably ensue. I don't believe in the least that this should become one of those fora thought-policed by ruthless moderators, but since (especially since it is hosted by a website dedicated to a single rifle cartridge) this forum offers such an amazing variety of categories discussing dozens or hundreds of firearm-related topics, I believe we owe it to each other to choose the threads best-suited to the interests or topics we wish to discuss, or create new ones.

I suppose by now I'm about due for a dose of my own medicine, and should return to topic myself: If, by "the M240 action", you mean one in which a carrier cams the bolt, or a part thereof, in a direction perpendicular to the bore axis in order to lock against a shoulder or recess of the receiver or barrel extension, the original BAR, Tokarev, StG-44, SKS, and FAL all qualify. The RPD (two tipping lugs/shoulders) and even the Ithaca 37 shotgun (albeit in manual form) could be said to qualify. Now, as for the last proposal,

"It seems like you could minimise the weight by building it around a trunion with rearward extentions to support the locking shoulder. It would be probably heavier than an AR, AK or Garand action, but it might be worth it - especially if you were developing a Stoner-style system or family of weapons..."

A friend proposed something similar a few weeks ago, and it occurred to me that the issue with trunnionizing a tilting-bolt such as a FAL or SKS would be the need to support the rear of the bolt--which means that the extension or trunnion must be the length of the barrel shank, plus the full length of the bolt, plus some meat behind the shoulder: basically the whole receiver, minus a bit of magwell and piston support, and a few inches of bolt carrier rail--a savings of mere ounces. Of course, they've done it in the 240 (although I'm not sure what exactly the extension looks like--any chance you have a diagram of that?), but that's a machine gun weighing about thirty pounds.

Obviously, using a shorter bolt (if it could be properly aligned) or a shoulder/lug farther forward (like the one in a Mossberg 500) would let you shorten the trunnion considerably, but I'm not sure if a single lug of a practical size would bear full-power rifle pressures, or if off-axis support would compromise accuracy. Maybe twin, opposed lugs (like the RPD)? Does anyone know if the receiver stub included in parts kits is long enough to retain the locking recesses? That might make an interesting project--an RPDM.

Take care,
Mike

I think Essay correctly assumed that any evolution of the M240 would NOT produce an assault rifle, but something heavier in duty cycle - such as a SAW or AR – and this thread may therefore not be the most appropriate one. With respect to all of the thread drift, I think each of those excursions helped inform the discussion by ferreting out what goals an assault rifle should seek to satisfy. Even something as far a field as squad size or the presence or absence of a dedicated grenadier has the potential to dramatically affect the weight, ROF and max mag capacity of a proposed Ideal Assault Rifle.

With respect to all of the thread drift, I think each of those excursions helped inform the discussion by ferreting out what goals an assault rifle should seek to satisfy. Even something as far a field as squad size or the presence or absence of a dedicated grenadier has the potential to dramatically affect the weight, ROF and max mag capacity of a proposed Ideal Assault Rifle.

No doubt--the size and composition of the infantry or SOF squad directly affect the characteristics of the infantry or SOF rifle. I did not by any means intend to criticize posts debating how such a rifle should interact tactically, and possibly combine or interchange basic platforms with, grenade launchers, shotguns, SAWs, etc., and if you believe I did, I apologize. What I said was that any time anyone brought up one of those perfectly-relevant topics, the discussion tended--mostly in the early pages--to jump the tracks to debates on the relative merits and technical details of various non-organic fire support--heavy crew-served weapons and vehicles, artillery, and even aircraft. Recently, I've appreciated the shift in the discussion back to the meat and potatoes of the rifle's role and desired characteristics--for which I hope you'll forgive my insatiable appetite.

Mike

Mike,

I think your focus on the minute details of assault rifle construction are just as valid and useful as any other. My interest is usually at a higher level of generality but my interest is in no way "better" or more useful. I came here to learn. Sometimes I ferret out something - usually in scale - that is going unnoticed and feel it important to share, but it’s really a lot more interesting when people with lots of different interests and focuses come together.

Now, back to the meat and potatoes, does anyone have a better diagram as I still can't figure out how the M240 action works. A close-up photo would also help a lot.

Hey, I think Daniel Watters just found us the perfect home for the M240 lite thread.

http://www.65grendel.com/forum/showthread.php?p=6747#post6747

The MRBS and MRBF numbers for the FN MAG-58/M240 are what interested me. No question that a rear-locking weapon is going to be heavier.

My interest is not in tilting bolt actions in general, but the M240 action in particular. I think one of the resons it is so reliable is it is locking against a shoulder extending accross the receiver with space all around it. That maked it unlikely that enough gunk can accumulate to keep it from locking. (Disclaimer - all my knowledge of the M240 is from reading. The Army still used M60s when I was in.

I think a front locking action with primary extraction (M1/M14/AK) and appropriate operating toleranced would put up good MRBS and MRBF numbers. Question is how to drive it. When was the last time anyone looked at primer actuation? The SPIW project?

Speaking of MRBS and MRBF, does anyone have numbers for the AK? I'v found numbers for the Diemaco C8 and some other modern ARs on the web, but not the AK...

I just stumbled accoss a quote online from A Rock in a Hard Place, Collector's Grade Publications' BAR book. It says there was a proposal between WWI and WWII to produce a lightened semi-auto BAR, but the Infantry Board didn't want detachable 20-round mags. The quote suggested much of the BARs weight was designed in to handle the heat generated in automatic fire. Looks like I'll have to add another Collector's Grade title to my collection...

Okay, I'm gonna feel like a real dunce asking this, but I gotta.
What do the acronyms MRBS and MRBF stand for?

Mean Rounds Between Stoppages / Failures.

http://www.google.com/search?hl=en&newwindow=1&safe=off&q=acronyms+MRBS+and+MRBA&spell=1

Just an update for you guys, as a continuation of a couple months ago, when I posted some of the the MGI Modular AR15 weapons platform.
Since then, we've done some more developing, and here's a rather incomplete picture of the current system, lacking the AK mag and the 308 cartridges, but I think you get the idea. Yep, that's an M14 mag, and it fits!
http://photos.ar15.com/WS_Content/ImageGallery/Attachments/DownloadAttach.asp?sAccountUnq=53166&iGalleryUnq=1956&iImageUnq=45126


BTW, we do have a belt-feed module that slides on to our modular attachment points of the existing lower.
This will provide entry, duty, sniper, and SMG and LMG functions with our system, all on one platform with minimal redundancy in additional parts to carry or buy to make desired reconfigurations.
We have already filed the solicitation paperwork for the TACOM carbine trials, and for the ARDEC trials for a new LMG. We will be submitting the same platform for each trial, and including the modular parts that would be required in that role. As far as I know, we are the only people to ever submit the same weapon for carbine trial and LMG trial, by just varying the configuration.

Our existing QCB system already meets the 20-second barrel change requirement for the LMG, and our new barrels will meet the continuous-ROF requirement and the wear-life requirement, and the receiver will meet the 50k-round lifetime requirement. So, we're in the ballpark. Our new "high-reliability" action parts, open-bolt FCG, and RateReducing/RecoilReducing Buffer will round out the package. We also offer the option of belt-fed or mag fed, with only a small easy change to the magwell. The belt-feed mechanism installs or removes in about a minute total.

The same platform is going in to the carbine trials with a box-fed magwell system, and a handguard that is equipped to accept the M203 launchers. Same "high-reliability" action group, RRB buffer, and selectable Open-bolt/Closed-Bolt FCG.

The exciting news is that this platform is quickly and easily configurable into any caliber necessary from 5.56 to 7.62x39 or 5.45x39 or 308 in box mag or belt-feed. Other calibers like 6.5G or 6.8SPC, etc, can also be used in box mags just as easily. No tools required for any of the changes, and they are QUICK. The entire package is light, manuverable, and effective. It also follows most of the same basic training manual-of-arms(some changes), and uses most of the existing parts inventory already available in the arsenal, such as barrels, mags, and most other parts, because it is an AR15-based platform. All the options such as optics, lights, lasers, iron sights, etc, are all immediatiely compatible.

This same platform is easily configured into a "sniper grade" accuracy platform in any of the above mentioned calibers as well.

And it configures into pistol caliber and rimfire calibers too, if needed for those roles.

This project is aimed at making one platform for all small-arms roles in the squad/platoon. It will be an interesting ride.

Tom, that's some fascinating engineering. Hope it goes well for you guys!

John

wow...just what I always wanted...a weapon that I can configure to whatever caliber I want....

is there going to be a civvie semi auto only variant of the trigger group
:whimper:

TWL,
Best of luck. I have been really impressed that several of us here have begun to look seriously around the world to see what else is out there beside the offerings of the FN monopoly. I was going to challenge Arne to aspire to more than an adaptation of the M249 - like that POS is the end all and be all of LMGs. FN is just one more huge defense contractor that uses its muscle to stomp out other better ideas. After the Clinton admin's relentless drive to reduce the number of defense contractors we now have the few who are left making it top priority to monopolize all of the time and attention of those in the DOD charged with weapons procurement. It looks to me that the Israelis and X-ComBlock stuff is at least the equal of the FN stuff.

I think your platform, with its support of intra - mission reconfiguration, will be put to uses you never imagined.

Q: will you be responding to the USMC sources sought program for a new AR?

TWL,
Great system and great posts. I like your QCB system as well and wish you and MGI the best with your military trials. I don't get a warm and fuzzy, though, when I see the detached barrel pictures on your site.
Barrel with Tube (http://www.mgimilitary.com/qcb.htm)
I don't know if there's some sort of guide arrangement under the handguards to cushion and funnel the barrel into proper alignment in the receiver, but it seems as though any degree of play in the system would allow a gloved, nervous, or otherwise fumblefingered shooter to peen the receiver end of the gas tube a bit if he slid the barrel back hard, and just a bit off-center. Even if there were tracks or tabs in place to guide it during changes, the skinny tube itself, unshielded and projecting aft an inch or so past the barrel extension, doesn't seem destined for a long life under field conditions. Is there any way to retain the tube inside the handguard, so that a slightly-beveled orifice on the gas block (where the shooter can see it as he changes barrels) could receive the very small projection at the forward end of the tube?

Keep up the good work,
Mike

TWL,
Great system and great posts. I like your QCB system as well and wish you and MGI the best with your military trials. I don't get a warm and fuzzy, though, when I see the detached barrel pictures on your site.
Barrel with Tube (http://www.mgimilitary.com/qcb.htm)
I don't know if there's some sort of guide arrangement under the handguards to cushion and funnel the barrel into proper alignment in the receiver, but it seems as though any degree of play in the system would allow a gloved, nervous, or otherwise fumblefingered shooter to peen the receiver end of the gas tube a bit if he slid the barrel back hard, and just a bit off-center. Even if there were tracks or tabs in place to guide it during changes, the skinny tube itself, unshielded and projecting aft an inch or so past the barrel extension, doesn't seem destined for a long life under field conditions. Is there any way to retain the tube inside the handguard, so that a slightly-beveled orifice on the gas block (where the shooter can see it as he changes barrels) could receive the very small projection at the forward end of the tube?

Keep up the good work,
Mike

Thanks.

The QCB has bevelled entry surfaces to "guide" the gas tube into its hole, and some smaller ones for the barrel. Perhaps this may not be enough for some people who are "fumble fingered", but it has proved to be workable without damaging the tube, and still be quick. I have used this system in the older style QCB for almost 3 years, and I can change barrels in less than 20 seconds and I've never even made a nick on my gas tubes. However, yes it is possible that someone could damage the gas tube if they inserted it wrong and applied some force to it.

Since the gas tube is not retained at the receiver end by anything, it really is not feasible to detach it from the gas block or FSB end when changing barrels. The barrel must have the bolt disengaged in order to release the barrel for changing, and thus the carrier key is backed-off its engagement with the gas tube when changes are made.

For LMG use, where rapid barrel changing is normally a necessity, we have developed a barrel which releases heat better than typical barrels, and thus will not need barrel changes as often in our system. So, we should have more rounds between barrel changes, and we still do meet the time requirement for barrel changes in the LMG trial. It is even possible that our barrel may not even require any change-outs to meet the continuous rate-of-fire requirement that is stated for the LMG trial. However, we're not depending on that.

Perhaps there are some things that we can do to make the system more "soldier proof". This will come if things happen during the upcoming trials that show the need for it.

TWL,
Best of luck. I have been really impressed that several of us here have begun to look seriously around the world to see what else is out there beside the offerings of the FN monopoly. I was going to challenge Arne to aspire to more than an adaptation of the M249 - like that POS is the end all and be all of LMGs. FN is just one more huge defense contractor that uses its muscle to stomp out other better ideas. After the Clinton admin's relentless drive to reduce the number of defense contractors we now have the few who are left making it top priority to monopolize all of the time and attention of those in the DOD charged with weapons procurement. It looks to me that the Israelis and X-ComBlock stuff is at least the equal of the FN stuff.

I think your platform, with its support of intra - mission reconfiguration, will be put to uses you never imagined.

Q: will you be responding to the USMC sources sought program for a new AR?

We recently received an official written request from a key officer in the Marine Corps, to provide a group of MGI Modular guns/systems in the various calibers, for an extended testing/training over the summer months. I think that this is for Marine Corps special operators. We have also received a similar request from the Army Special Forces groups which are already in the sandbox, and we have already provided some T&E product to Navy special operators. Nothing from the Coast Guard yet, but I suspect that when they hear the word from the Navy Boarding Teams, they will be interested too. The overall impression from all these groups is that they like the system, and want it NOW. They are going to test it ASAP, and once it passes muster, they want to implement it right away. I don't think that it will necessarily be going to the general forces right away(if ever), but it do think it will find a home in the special operations groups of all branches pretty quickly.

wow...just what I always wanted...a weapon that I can configure to whatever caliber I want....

is there going to be a civvie semi auto only variant of the trigger group
:whimper:

I don't think that the ATF currently views Open Bolt operating systems if a very acceptable way, for civilian use. In any case, there is no advantage for any form of Open Bolt fire-control in a semi-auto weapon, unless you are bump-firing or something that produces an overheated condition that would cause cook-offs.

We will definitely provide both the Open Bolt Full-Auto-Only FCG, and the Selectable Open Bolt Full/Closed Bolt Semi FCG for "drop-in" application for any M16 Registered Receivers. These FCG's do not work with DIAS, and are for military style M16 auto sears only. Any civilian with an M16 RR on a Form 4, or Post Sample, can drop these fire-control kits into their RR without any mods to the receivers. These will be expensive kits, but they are unique.

For the military use of the M16 version of our MGI Modular Lowers, they have "beefed-up" receiver thickness in the hammer pin area for added strength, and also the modular magwells overlap the hammer pin holes, so that the hammer pins are inherently captured when the modular magwells are installed, and no "walking" of the hammer pin is possible with our package. All our receivers have these feature, but it is primarily of interest when using the Open Bolt FCG type kits that can place added stress on the pins and holes.

Thanks.

The QCB has bevelled entry surfaces to "guide" the gas tube into its hole, and some smaller ones for the barrel. Perhaps this may not be enough for some people who are "fumble fingered", but it has proved to be workable without damaging the tube, and still be quick. I have used this system in the older style QCB for almost 3 years, and I can change barrels in less than 20 seconds and I've never even made a nick on my gas tubes. However, yes it is possible that someone could damage the gas tube if they inserted it wrong and applied some force to it.

. . . .

Perhaps there are some things that we can do to make the system more "soldier proof". This will come if things happen during the upcoming trials that show the need for it.

I must admit to a long-standing skepticism of the robustness of the basic AR-15 design, having as the heart of its operating system (for lack of a better term) a tin straw. Now, carrying around said capillary tubing on a spare barrel, in anything but a heavy hardcase--I wouldn't bet on it making the two-hour trip from here to my land in the cluttered back seat of my truck, much less being "soldier proof"--but I'll defer to your extensive experience with the system in the absence of any on my part. I'm glad someone out there is innovating, especially in the area of quick-change barrels; I love the idea, and can't understand why it's not more prevalent on ARs--with their streamlined barrel/extension units.

Thanks,
Mike

Mike,
The gas tube may very well prove to be a weak point of this system, in light of some rough use involved in carrying things around.
However, since I've carried some around alot for about 3 years now with my system, and even had them survive airline baggage handlers :eek: , they are surprisingly robust even when exposed.

Of course, we do have an overhead piston design on the design table, which can have the op-rod retained in the handguard during barrel changes, so if we need to implement that, we can.

We'd prefer to be able to retain the Direct Impingement gas system if possible, due to its inherent advantages over the overhead piston/op-rod design, but we can use the overhead piston system if necessary. Mack designed his first overhead piston-operated rifle over 35 years ago, so that is not anything new to him. It will be an easy switch, if needed. Also, with gas piston systems becoming the "flavor of the month" lately, we may need to respond to the commercial market forces, and produce an overhead piston system for our QCB anyway. This way, the consumers can have the gas system that they prefer, for whatever reasons, and we can avoid any arguments about the merits and drawbacks of various gas system implementations during conversations with our customers. It could simply be in keeping with our modular design, to have a selection of gas operating systems too.

Actually I was talking about the modular AR platform, not nessicarily the open bolt "MG" systems. Sorry for the confusion.

We recently received an official written request from a key officer in the Marine Corps, to provide a group of MGI Modular guns/systems in the various calibers, for an extended testing/training over the summer months. I think that this is for Marine Corps special operators. We have also received a similar request from the Army Special Forces groups which are already in the sandbox, and we have already provided some T&E product to Navy special operators. Nothing from the Coast Guard yet, but I suspect that when they hear the word from the Navy Boarding Teams, they will be interested too. The overall impression from all these groups is that they like the system, and want it NOW. They are going to test it ASAP, and once it passes muster, they want to implement it right away. I don't think that it will necessarily be going to the general forces right away(if ever), but it do think it will find a home in the special operations groups of all branches pretty quickly.


FYI, in case you missed it, the Marines are now part of SOCOM. Those forces are designated MARCOM.

TWL,
Thank you again for all the information, and for continuing to push the info to us here in the forum, as your colleagues at both MGI and ABS push the envelope of weapon design. Your previous posts have done a great job of laying all the facts on the table as regards gas impingement vs. gas piston, although I remain a recoil dinosaur myself :cool: .

I think the gas tube issue is probably (as the difference between my first impressions of the pictures, vs. your real world experience, has illustrated) one of perception and customer confidence, rather than mechanical reliability. MGIs products (upper and lower) exude an air of massive ruggedness; that forend looks like something one could use to deflect a buttstroke, then retaliate in like fashion alongside the offending party's head, and the lower quickly overcame any initial apprehensions I had (since I was also looking at designing a universal lower, but from a different angle) when a friend described it as being split between the pins. Then one looks at that little gas tube, alone and unafraid . . . But, if it works it works, and the best advertisement is proven superior performance in the field.

On a slightly-related note, a friend at work asked me yesterday if he could use me as a reference for a vexing Engineering Management question regarding reliability testing. While I knew the answer from my personal interest in design and engineering, I questioned whether his graduate-level engineering professor had other ideas in mind for a "documented outside source" than a colleague with a BS in History. Had I known that an innovative manufacturer like MGI was shifting old paradigms and exploring new efficiencies in reliability testing by subjecting its products to the tender mercies of airline baggage handlers, I could have solved the problem on the spot. That's better than running over them with a truck!

Take care,
Mike

Mike,
You'll be happy to find out that Mack is also a "recoil dinosaur", and he has a recoil-operated gun in the prototype stage that is designed to compete in the price territory of the Mini 14 and Kel-tec 16. I just can't stop this guy from designing new stuff!

Regarding the durabiltiy tests of the airline baggage handlers, that is simply an anecdotal test(although repeated many times), and it is quite possible that the next time the barrels may be completely twisted into pretzels with the gas tubes wrapped aound them! These baggage handlers are not to be underestimated!
Seriously though, we can see that the gas tube is a more delicate thing than the barrel itself, and if we have to do something about that, we will.

The recoil operated comments reminded me of this. The other day I saw a cutaway of Benelli's inertia operated shotgun action. The weapon recoils against a spring in the bolt carrier. The bolt carrier wants to stay at rest (inertia). At some point, the compressed spring forces the bolt carrier to the rear.

It occurred to me that one might modify an M16 bolt and carrier to operate on the inertia locking system. You'd need to get rid of the raised portion of the bolt shank where the gas rings are. Then you could put a spring around the bolt shank in the gas cylinder in the bolt carrier. You'd also need to shave the front of the bolt carrier so it could move forward as the spring compressed.

Why? To see if it would work. The gas operated system is probably more reliable, but an inertia locked system might yield higher velocities (no gas bleed).

Spartiate has also got me thinking more about recoil operation and constant recoil.

FYI, in case you missed it, the Marines are now part of SOCOM. Those forces are designated MARCOM.

Not quite, it's actually MARSOC. And not all Marines are in it. Just a small detail but I thought I would let you know.

Mike,
You'll be happy to find out that Mack is also a "recoil dinosaur", and he has a recoil-operated gun in the prototype stage that is designed to compete in the price territory of the Mini 14 and Kel-tec 16. I just can't stop this guy from designing new stuff!

Regarding the durabiltiy tests of the airline baggage handlers, that is simply an anecdotal test(although repeated many times), and it is quite possible that the next time the barrels may be completely twisted into pretzels with the gas tubes wrapped aound them! These baggage handlers are not to be underestimated!
Seriously though, we can see that the gas tube is a more delicate thing than the barrel itself, and if we have to do something about that, we will.

You wouldn't be F'ing with me about that recoil action, would you (drool, drool)? We do have an Eighth Amendment. Once it passes the baggage-handler test ;) , consider me signed up.

Thanks again,
Mike

The recoil operated comments reminded me of this. The other day I saw a cutaway of Benelli's inertia operated shotgun action. The weapon recoils against a spring in the bolt carrier. The bolt carrier wants to stay at rest (inertia). At some point, the compressed spring forces the bolt carrier to the rear.

It occurred to me that one might modify an M16 bolt and carrier to operate on the inertia locking system. You'd need to get rid of the raised portion of the bolt shank where the gas rings are. Then you could put a spring around the bolt shank in the gas cylinder in the bolt carrier. You'd also need to shave the front of the bolt carrier so it could move forward as the spring compressed.

Why? To see if it would work. The gas operated system is probably more reliable, but an inertia locked system might yield higher velocities (no gas bleed).

Spartiate has also got me thinking more about recoil operation and constant recoil.

I don't know if the Benelli action will handle HPR pressures, but if it does, I am there! I look forward to all our future ventures with mixed feelings--eager anticipation, uncertainty as to whether we can succeed . . . and a bit of apprehension as to the staggering economic (not to mention marital) consequences, as we all rush to the store to buy each other's products! :D

Keep rocking,
Mike

No, it is a real prototype, and we had it at the SHOT Show, but kept it under the table and only showed it to a few people.

It is avaliable in 2 versions.
1 is a straight-pull-bolt-action side-charging rifle for California and other restricted markets.
The other has the recoil operating mechanism in it for semi-auto capability, and is also side-charging handle.
They are both built on the concept of "tube guns", and use AR15 mags, but can easily be made for any of the calibers.
They are both basically the same gun, and one has the recoil mechanism and one doesn't.
It is possible to include take-down capability for this gun, but I don't know if we'll include that as part of the initial package. Uses standard AR15 barrels and magazines and fire-control parts and buttstock.
Same inherent accuracy as an AR15, and would make a nice 6.5 Grendel package at lower cost.

TWL, that sounds really cool. MGI and ABS are my favorite companies right now.

Can you give us any more details on its operation/operating components of the recoil operated rifle w/o IP issues? After reading the post above, it occurred to me that if you let the AR barrel recoil a fraction of an inch, that would give the bolt carrier the momentum to do its thing. If that's how it works, how do you get the AR's inherent accuracy with a moving barrel? REAL precise bushings?

Spartiate, I saw a photo of a 5.56 version of Beretta's Storm. It looked like it was based on a shotgun action (presumably Beretta's gas operated one). I had that in the back of my mind when I had the inertia-operated AR idea...

Does anyone have any more infor on the Beratta? Was it at SHOT?

Essayons,
Thanks!

Actually I was referring to the straight-pull bolt action version, when I mentioned the inherent accuracy part, but the recoil operated should be good too.
I can't get into any details about the action right now, but I think you have a good grasp of this recoil operation thing, and there are only a few ways to do it.
I think this rifle, when it eventually comes out, will be a nice alternative the the Mini-14 or KelTec rifles, in the low priced market.

TWL and Essayons,
I have my suspicions as to how it could be done, since the AR was a gas-op development of the recoil-op Johnson M1941's basic bolt system--another concept with great potential, shelved because of poor execution the first time around (old paradigms and wartime pressures--perfect candidate for the Decon thread). If you could refine that design, you'd have my gratitude (and probably my check, via my friendly neighborhood FFL).

Take care,
Mike

I was thinking about a recoil-operated AR upper while dozing off last night. Here's the jist of it:

1. A barrel shroud (carbon fiber?), perforated for heat management, with a bushing attached where the gas block would normally be and an integral barrel nut. You'd slide the barrel in from the rear. The front of the barrel flange would rest against the back of the barrel nut and the front of the boss that normally rests against the handguard cup would rest aganinst the back of the bushing. You'd attach it with a strap wrench or provide for an external wrench like one-piece carbon-fiber free-float tubes.

2. An upper with the front face of the barrel extension area shaved to permit the barrel to move a short distance into the upper to push the bolt carrier rearward. Admittedly, this would require some engineering - maybe some kind of buffer between the steel barrel flange and the aluminim upper, so the upper wouldn't get deformed over time where the barrel flange battered it.

3. Something like David Tubbs' carrier weight system so you could tune the recoil-operated system for different ammo.

Okay, here it is, by popular demand. The SAW/AutoRifle version of my bullpup design with an inverted saddle drum (like off the MG15) that rides in front of the operators face, but not so close as to bang them with recoil. The standard mag would mount similar to the P90 so that you can use the "stick mags" in an emergency, or slap in an adapter and use standard AR mags in a pinch (bren style).

This is just a concept sketch, I promise the final design will be a bit more...elegent. Still deciding on the internals, but I am pretty set on a gas tappet operated system...though if someone could convince me to use recoil, I would be willing to change the design. :D

PS: Thats a 20 inch fluted barrel. yah I know the carbon fiber wrapped stuff is in vogue, but I just went with something to make it obvious. Also, with the 20 inch barrel, its only a little longer than an M4 and the sights (though not very detailed in this drawing) are at the same height above muzzle.

Nice! But not "nose to charging handle" equivalent cheek-weld with that saddle drum where it is.

Nice! But not "nose to charging handle" equivalent cheek-weld with that saddle drum where it is.
Please elaborate?
I'm still working on the ergonomics of the stock to avoid nose bashing with the drum....since all I have to work with is rough approximate numbers its going to take a little trial and error, but my guestimation is that a slight extension of the P90 stock so that the cheek doesn't rest over the magazine/mag well with it shouldered should be possible while still keeping the length of pull reasonable.

And for those of you out there, like me, that are fans of the Ultimax, Special Weapons has an article on it and the 6.5 grendel this month. Not to mention the resurgance of the .45 cal service pistol...but thats another kettel o' fish.

I'm not trolling - I like your idea. Just look at your image and think about where the tip of your nose would be if your eye was as close to the rear sight as it would be if your the tip of your nose was on the charging handle (I may have typed "carrying handle" before) of an AR. It looks like it would put your cheek hard on the back of the left side of the Beta C mag. I'd have to handle a mockup to know for sure... Again, no flame intended.

BTW, IMO a 6.5G Ultimax would be suhweet!

Aaaah, I see what you are saying now. Yes, distance to the rear sight is a little long (for various reasons, and I have a couple of solutions I haven't gotten to yet for that), but the actual sight height and alignment would be correct. Think of it more like the AK sight placement and radius than an AR, but at the same height above bore as the AR. Oh, and that empty space isn't a carry handle. Its actually where the P90 style magazine would ride if the Beta/Saddle drum were not in place and you had to grab someone elses mag

PS I was looking at the Ultimax 100 and imagining it inverted and bullpupped...now that would be an awsome LMG/SAW/IAR with a saddle drum..

Exactly. As long as the Beta-C Mag isn't bashing my front teeth, I don't care so much about the sight location. It's more about the relationship between the butt plate and the back of the left side of the C-Mag. You can compensate for the eye-to-aperture distance by manipulating the size of the aperture (although I prefer it closer, rather than farther from my eye). Eye relief could also be critical with shorter eye-relief optics. The nose to CH comment was more to put things into a commonly understood frame-of-reference.

well, I am still tinkering with the ergonomics and I understand your concearn. My main solution is to make the stock adjustable for length of pull so that you can pull it and the cheek weld/rest back far enough to be comfortable. the "mag well" should be out of the way if I tinkered right. Unless someones willing to do a mockup for free (kinda broke you know), I won't know till I get further along in the design process.

Coolhand, if you place the saddledrum directly above the pistolgrip, "similar" to the M-60, you would get the drum out of the way, but would have to abandon the bottom-ejection.

Altogether, you would then get a shorter weapon than a conventional Ultimax, but with better ergonomics than a bullpup with a drum.

Also, you should think about off-set sights, as that would improve accuracy with conventional magazines.

That would be a solution using already tried and tested designs.
Unfortunately Im not sold on the P-90 style magazine yet, especially not in larger calibres, but if you are able to make a reliable and compact hi-capacity design it would be very interesting. Especially since it probably would be a lot more compact than a drum.

Coolhand, if you place the saddledrum directly above the pistolgrip, "similar" to the M-60, you would get the drum out of the way, but would have to abandon the bottom-ejection.

Altogether, you would then get a shorter weapon than a conventional Ultimax, but with better ergonomics than a bullpup with a drum.

Also, you should think about off-set sights, as that would improve accuracy with conventional magazines.

That would be a solution using already tried and tested designs.
Unfortunately Im not sold on the P-90 style magazine yet, especially not in larger calibres, but if you are able to make a reliable and compact hi-capacity design it would be very interesting. Especially since it probably would be a lot more compact than a drum.

+1 - sort of like a top feed FG42.

not a bad idea...like I said, still morphing out the problem. Thanks for the input.

Mounting a Beta-C type saddle drum on the left side of the receiver behind the pistol grip might permit you to integrate the curvature of the "top" half of the saddle drum into the cheekrest and permit you to use a side mounted mag without unbalancing the weapon (the axis of the top drum would be over the bore and the axis of the bottom drum would be under it). However, that would result in a very high sight plane. Just a thought.

Gee, I had this wonderful idea for a reverse pump underbarrel rig like a stubby neostead....
someone beat me to it.
http://www.inl.gov/featurestories/2003-12-22.shtml
crap crap crap

Gee, I had this wonderful idea for a reverse pump underbarrel rig like a stubby neostead....
someone beat me to it.
http://www.inl.gov/featurestories/2003-12-22.shtml
crap crap crap

Why not use your P90-mag-ideas with a 40mm... Then you could get a lot of firepower in a very much more compact package than the current 40mm six-shooter...

because not every trooper needs a GL. The design was for an underbarrel "masterkey" type system that could also be used to fire lethal and non lethal application shotgun rounds. Basically I was going for a "Morita/M41A pulse rifle" arrangement with a 6.5 Grendel upper barrel and a 12 gauge shotgun under barrel.

It was just an idea that struck me... Not that every soldier should have a UGL, but rather that a designated grenadier could have a more practical weapon than the MGL-140.

An underbarrel shotgun should also be possible with a similar design... And it could be a lot more compact and elegant than the Alien-gun...

Actually the one I posted about earlier is close to what I envisioned. Only thing different is the addition of a box mag. I would rather have a tube mag with a cut off for hand loading...and actually the design I had in mind could be slid open further for extended length ammunition (like flares).

Okay, here it is, by popular demand. The SAW/AutoRifle version of my bullpup design with an inverted saddle drum (like off the MG15) that rides in front of the operators face, but not so close as to bang them with recoil. The standard mag would mount similar to the P90 so that you can use the "stick mags" in an emergency, or slap in an adapter and use standard AR mags in a pinch (bren style).

This is just a concept sketch, I promise the final design will be a bit more...elegent. Still deciding on the internals, but I am pretty set on a gas tappet operated system...though if someone could convince me to use recoil, I would be willing to change the design. :D

PS: Thats a 20 inch fluted barrel. yah I know the carbon fiber wrapped stuff is in vogue, but I just went with something to make it obvious. Also, with the 20 inch barrel, its only a little longer than an M4 and the sights (though not very detailed in this drawing) are at the same height above muzzle.


Normal adult length of pull is only what, 13 inches? Your drum might need to be further forward to avoid problems.

OR, maybe you could design it to be used as the cheek rest.

Yah, actually I had planned to make the stock adjustable, with a settable length of pull, collapsable for storage and carry, adjustable for proper length of pull. I noticed the issue with the double drum right off, but like I said, that was a concept drawing, not a final design.

I'm actually revamping the design. Basically I'm going to try to use as many "existing" componants, potentially from the AK and AR as a base line. Similar to the MGI reciever concept which uses standard AR internals, barrel, gas tube, but a change to the reciever and the addition of a couple of camming levers, and the standard barrel becomes quick change. I currently have a somewhat drop in design based on the AK, but I would prefer the AR. I have some specs on the ARs, but none of the internals. If Ihad I would have probably started with the AR.

A concept picture will be forthcoming after I get an AR and do more research.

I found this (http://world.guns.ru/assault/as78-e.htm) on guns.ru...

It seems to be a modernized FG42, made as a possible replacement for the M16 during the Vietnam-era...

Interesting piece of could-have-been...

Interesting how the "low Maintinence" aspect of it included a side mounted gas piston. I've been wondering if I couldn't engineer a dual gas piston type system into the P90 style design I have in mind.

ONe of my other thoughts Had been a side mounted "sten" or FG42 style magazine setup, so that you could use a low profile high cap mag, OR standard magazines and drums. The only issue is that it reduces the ambidexterity of the design, and a perfect design would be completely ambidexterous.

One thing I liked about the Calico M900 series was the placement of the safty and bolt release. The rest of the weapon may not have been quite up to par, but the ergonomics were quite good.

And now for something completely different...

Coolhand, I stumbled accross THIS (http://world.guns.ru/assault/as74-e.htm) and thought it might interest you if you had not already seen it.

"During mid-1950s, Soviet Army initiates new trials for improved assault rifle design in the same 7.62x39 M43 caliber. Korobov submits his improved TKB-517 rifle, still based on the Kiraly type delayed blowback action; this weapon was extensively tested against modified Kalashnikov AK rifle, as well a number of other designs, and found to be superior to all. Korobov was found to be most accurate and controllable in full automatic mode (primary mode of fire, according to Soviet tactical doctrine), especially when fired from the shoulder or from the hip. It was also significantly lighter and less expensive to make than modified AK. Nevertheless, Soviet Army preferred less effective, but familiar and already well established Kalashnikov AKM over the more effective and lighter, but entirely new design." (Emphasis added).

There's more information about the '50s trials and the Abakan trials in Assault Rifle by Maxim Popenker and Andy Williams. It's a good read if you haven't already done so.

http://world.guns.ru/assault/korobov_tkb517.jpg

From what I've read, only the French have built on Kiraly and Koborov's retarded blowback system. They used variations of the Kiraly system in the A-AT52 machine gun and in the FAMAS. The A-AT52 lost out to the M240 in US trials, but from what I've read, the FAMAS has served the French well.

Last night I was reading about the AEK-971 and AEK-974 in Popenker & Williams' book Assult Rifle. I don't have the book in front of me, but here's some information I found online about the AEK-971/974's balanced action. It looks like it paraphrases the book closely:

"Key feature of the AEK971 is gas driven, balanced action with rotating bolt barrel locking. Balancing mean that AEK971 gas drive has two gas chambers and two gas pistons. First gas piston is linked wia gas rod to the bolt carrier an moves as usual. Second gas piston is linked to the balancing msteel weight and moves in opposite (to main gas piston) direction. This design is implemented to eliminate 3 of 4 total impulces of the movement that affect rifle during the full-auto fire. 1st impulse rifle received when bullet moves along the barrel - this is recoil itself. Second impulse rifle received when heavy bolt carrier/bolt group moves along the receiver back and forth. Third impulse is received when bolt carrier/bolt group stops in the rear position and fourth - when this group stops in forward position after new cartridge is chambered. Synchronous and opposite movement of the balancing weight eliminates all except the recoil impulse, so rifle becomes far more stable during full-auto fire."

"The gain of accuracy in full auto is whole 15-20%, when compared to AK-74 asault rifle in the same kaliber. The newly adopted by Russian army AN-94 assault rifle has slight edge over the AEK974 only in short burst (2 rounds only) mode. In full-auto medium or long bursrt fire mode (3-5 or 7-10 rounds per burst) AEK974 wins hands down..."

This got me thinking - What if you added a second bolt group instead of a countermass and two lightweight (berhaps carbon wrapped) barrels instead of one heavier one? Each barrel would only be subject to half the cyclic rate, so you could get away with lighter barrels and/or a higher cyclic rate. You might even be able to miniaturize one of the two-barrel Gast principle aircraft cannon discussed in Williams' book Rapid Fire, such as the GSh-23L.

I think Tromix did a dual AR design where the top one fired and the gas impulse operates the lower one, and vise versa. Is that what you had in mind?

http://tromix.com/Welcome.htm

its in the projects section, called the "siamese .223"

Actually adding a piston to the system to minimize fouling and using the gas tubes to run gas to the pistons would make it heavier, but I think would improve reliability. There is plenty of room between the twin mechanisms.

Tromix's siamesed AR isn't quite what I had in mind. The reciprocating massed have to be tied together (i.e. one has to move backwards as the other moves forwards) to eliminate three of the four action impulses. This is disscussed on page 175 of Assault Rifle (Korov Machine Plant AEK-971 and AEK-974). It doesn't appear that the bolt carrier groups of the siamesed ARs are tied together that way. In the AEK-971 and 974, the operating rod, bolt carrier and bolt are connected to and synchronized with the counter weight through a gear.

According to Rapid Fire "the German firm Gast devised a...mechanism for an aircraft RCMG, in which the recoil of each barrel operated the loading and firing mechanism of the other, leading to a high rate of fire of around 1,600 RPM. This principle was adopted much later, in the Russian GSh-23...and GSh30 aircraft guns and the 2A38 AA gun, all of which display the usual national characteristics of compactness, light weight and a high rate of fire, and the American GE 225. These guns all use gas to operate the mechanism..." (page 60) The diagrams on page 61 suggest that each side of these guns would provide the "synchronous and opposite movement" that the balancing weight in the AEK-971 and AEK-974, and the same 15% to 25% increase in full-auto accuracy. I don't know how reliable the GSh or GE designs are or whether they could successfully be scaled down, but that's where I'd start.

Each barrel would only be subject to half the cyclic rate, so you could get away with lighter barrels and/or a higher cyclic rate. You might even be able to miniaturize one of the two-barrel Gast principle aircraft cannon discussed in Williams' book Rapid Fire, such as the GSh-23L.I have waited years to find out more about the Gast action. The only thing I know about the action is it was once described as "two machine guns with a teeter-todder in the middle" Other than that is it extremely reliable, has a very high ROF, and for short bursts actually outperforms a GAU as the GAU takes a second or so to spin up. I am very interested in this gun for providing great firepower on CROWS turrets on light vehicles - the PAV especially - but even for something like a twin-fifty BMG on a HumVee. It is reported to be easy to maintain in the field - unlike a GAU - and has so little recoil that the Gsk-23 is actually available in a podded version for the MiGs for strafing. It would also be light and easy to man-handle on a skate mount or overhead power-assisted mount for the HOOOW's station. :D

I just can't believe that a gun that was designed in 1913 by a German and used extensively by the ComBloc has been so totally ignored in the West. Got diagram?

Actually, it wouldn't be hard to WECSOG one together as a prototype. I'd just need a couple of AR uppers and bolts, some JB weld, and some good hard steel to start with. Only problem is the BATF would probably come beat down my door because it would operate similar to an open bolt system...

With the "teetertoter" description, I can actually see it in my head. :D

Contact Tromix and suggest it. The nuts there might do it just for fun!

There are diagrams in Anthony Williams' books. I am looking for examples online. Here is a photo of the GSh-23 that suggests how it works.

You can see the "teeter totter" on top. The GSh's are gas operated - you can also see what I think are gas cylinders above the breach end of the barrels.

http://www.aviation.ru/gun/GSh-23-2.jpg

I think you could build a prototype from M16/AR15 components by (1) machining teeth into extended carrier keys that run the length of the bolt carriers and (2) using a gear to tie them together so that one runs forward as the other runs back.

This site LINK (http://ram-home.com/ram-old/indexq.html) contains a discussion of the original Gast guns. If you click on the "7.92mm" or "13mm" links it will take you to photos.

Rechambered for something like a 300 RSAUM this would put a smile on the face of every chopper door-gunner who ever flew. The reason I like it for the PAV is it can be maintained in the field. The PAV can go for such extended periods without needing any resupply that this is a big consideration in making max use of its great unrefueled range and crew sustainment features.

PS: Any idea how much this gun would weight in RSAUM or .338LM ?

A Gast type action has some interesting implications. You could make the bolt or bolt carrier on each side lighter than the bolt or bolt carrier in a comparable conventional action. For example, you could use lighter bolts in a siamesed straight-blowback action, because the mass of both bolts would be resisting the movement of the cartridge case.

I think there's potential to combine Gast's action and Kiraly's lever delayed blowback action (e.g. FAMAS (http://world.guns.ru/assault/as21-e.htm), Korobov TKB-517 (http://world.guns.ru/assault/as74-e.htm) and AAT-52 (http://world.guns.ru/machine/mg09-e.htm)) by having the delay lever act against the other bolt carrier instead of against a cross-pin in the receiver. The lever would act as both the "teeter totter" in Gast's designs and the delay lever in Kiraly's. If the gas assist on the GSh cannons work the way I think they do, then it could be applied to the Gast/Kiraly system to make it more reliable.

Standard AR15/M16 design, except with a gas-piston upper in 6.5 Grendel.
Assault Rifle: POF Gas Piston upper with 16" barrel
Sniper/DMR: POF Gas-Piston upper with 20" barrel
SAW/GPMG: Shrike upper with 20" heavy barrel with fluting

The KISS principle comes into play here. We already have our soldiers trained on the platform, and the only weakness in it is the direct impingement gas system and the weak 5.56 round. Eliminate those 2 issues and you have a winner.
It is accurate, reliable and easy to manufacture/maintain.

The KISS principle comes into play here. We already have our soldiers trained on the platform, and the only weakness in it is the direct impingement gas system and the weak 5.56 round. Eliminate those 2 issues and you have a winner.

I agree with you generally, but disagree that "the only weakness in it is the direct impingement gas system". I can think of two more important weaknesses: (1) the lack of initial or primary extraction (loosening the casing in the chamber before extraction) and (2) the use of a relatively long straight case. To the extent the M16's reliability is really worse than other assault rifles (such as the AK), those factors are at least as important as the gas tube, IMO.

As I've said, I'd love to see our military adopt MGI's modular lower with interchangeable magwells for M16, M14 and AK mag wells and dedicated uppers or MGIs Quick Change Barrel system. That would permit us to use 5.56x45, 7.62x51 or OPFOR ammo with minimal training or documentation changes.

I agree with you generally, but disagree that "the only weakness in it is the direct impingement gas system". I can think of two more important weaknesses: (1) the lack of initial or primary extraction (loosening the casing in the chamber before extraction) and (2) the use of a relatively long straight case. To the extent the M16's reliability is really worse than other assault rifles (such as the AK), those factors are at least as important as the gas tube, IMO. Don't forget what (in my limited AR experience) has been the most significant factor in combination with DGI / fouling: (3) the use of a cylindrical bolt bearing completely on a tubular upper, with minimal clearance for foreign matter. Contrary to popular belief (particularly as regards the AK), manufacturing precision and grit space are not mutually exclusive.

Take care,
Mike

Don't forget what (in my limited AR experience) has been the most significant factor in combination with DGI / fouling: (3) the use of a cylindrical bolt bearing completely on a tubular upper, with minimal clearance for foreign matter. Contrary to popular belief (particularly as regards the AK), manufacturing precision and grit space are not mutually exclusive.

Take care,
Mike

Good point Mike. I forgot to mention the relatively delicate magazine feed lips - the #1 source of problems, IMO, based on my limited experience and the anecdotal evidence I've heard.

I agree with you generally, but disagree that "the only weakness in it is the direct impingement gas system". I can think of two more important weaknesses: (1) the lack of initial or primary extraction (loosening the casing in the chamber before extraction) and (2) the use of a relatively long straight case. To the extent the M16's reliability is really worse than other assault rifles (such as the AK), those factors are at least as important as the gas tube, IMO.

As I've said, I'd love to see our military adopt MGI's modular lower with interchangeable magwells for M16, M14 and AK mag wells and dedicated uppers or MGIs Quick Change Barrel system. That would permit us to use 5.56x45, 7.62x51 or OPFOR ammo with minimal training or documentation changes.
While a modular lower would be nice, the idea of switching to 6.5Grendel is to limit the multitude of calibres stocked and carried by our armed forces. I don't think we will ever fight anyone that carries M14's or uses 7.62NATO for that matter. I can see a modular lower as being a great asset to spec ops teams operating far behind enemy lines, but the future of war seems a bit unclear as to when we will actually fight a conventional war again. I don't think any country on this planet is stupid enough to attempt to engage America in a conventional war - not after the events of the past 5 years :D
As for the Gas system, feed lips and extraction. It is near impossible to engineer a "perfect" weapon with no compromises. With a 2 stage extraction, you face complications - more small parts that complicate field stripping and can break and also more complex/expensive manufacturing. $0.05 is a lotta money when you are working with the numbers our military is working with.
As I mentioned before, the AR is far from perfect and the reliability issue is pretty much not an issue any more. With advances in propellants and metallurgy, most of the fouling issue has been taken care of. I still feel a Piston upper in 6.5 grendel is the way to go.
The AR is definitely a cut above the rest, accuracy and ergonomics wise. A bullpup would be nice because of the longer barrel, but that would mean a whole lotta R&D and lack of a convenient conversion to GPMG via just an upper and mag well block.

I don't think we will ever fight anyone that carries M14's or uses 7.62NATO for that matter.

Well, what about the Janjaweed-militia in Sudan... Also, I have seen several G-3s have been captured by american forces in Iraq.

Also, 7.62x54R is very common all over Africa and Asia, and will actually outperform 7.62 NATO...

Well, what about the Janjaweed-militia in Sudan... Also, I have seen several G-3s have been captured by american forces in Iraq.

Also, 7.62x54R is very common all over Africa and Asia, and will actually outperform 7.62 NATO...

...or god forbid, Pakistan. They still mfg the MG-42/MG-3 in 7.62x51 NATO

The Iranians have large numbers of G3 rifles and MG1 GPMGs; both fire 7.62x51.

The Iranians have large numbers of G3 rifles and MG1 GPMGs; both fire 7.62x51.


Yep, and G3 and FAL mag wells are probably on MGI's to do list.

I never said we might face an adversary using M14's. The OPFOR reference was to AK mags and ammo.

I think our military would be more likely to adopt a modular system that would permit the use of both 5.56x45 and 7.62x51 than an entirely new round. Among other things, there are significant logistical and political barriers to adopting a new round (most of our allies use 5.56x45 and/or 7.62x51).

MGI's system isn't "ideal" but it would be a logical evolutionary step, and a better idea, IMO, than something like the XM8.

At the moment, my "ideal" would be a cross between the M16 and AK firing something like 6.5 M43. M16 ergonomics, lightweight short stroke piston system (to minimize reciprocating mass), Sig 550 or Galil style two-lug bolt w/primary extraction, and a damned good medium weight barrel for accuracy. Something like the AEK-971 (http://world.guns.ru/assault/as34-e.htm) with better ergos in 6.5 M43 would also be pretty cool, too.

"AEK971 is being developed at Kovrov Machinebuilding Plant (formerly known as Kovrov Machineguns Plant) by chief designer S.I.Koksharov.

Key feature of the AEK971 is gas driven, balanced action with rotating bolt barrel locking. Balancing mean that AEK971 gas drive has two gas chambers and two gas pistons. First gas piston is linked wia gas rod to the bolt carrier an moves as usual. Second gas piston is linked to the balancing msteel weight and moves in opposite (to main gas piston) direction. This design is implemented to eliminate 3 of 4 total impulces of the movement that affect rifle during the full-auto fire. 1st impulse rifle received when bullet moves along the barrel - this is recoil itself. Second impulse rifle received when heavy bolt carrier/bolt group moves along the receiver back and forth. Third impulse is received when bolt carrier/bolt group stops in the rear position and fourth - when this group stops in forward position after new cartridge is chambered. Synchronous and opposite movement of the balancing weight eliminates all except the recoil impulse, so rifle becomes far more stable during full-auto fire.

The gain of accuracy in full auto is whole 15-20%, when compared to AK-74 asault rifle in the same kaliber. The newly adopted by Russian army AN-94 assault rifle has slight edge over the AEK974 only in short burst (2 rounds only) mode. In full-auto medium or long bursrt fire mode (3-5 or 7-10 rounds per burst) AEK974 wins hands down, being also some 0.5kg lighter than AN-94, simplier and cheaper to manufacture.

At the present time AEK971 in both 5.45x39mm and 7.62x39mm chamberings is being tested by Russain army in some quantities (my sources said that at least one hundred of AEK971s in 7.62mm was aquired by Russian army for field testing).

AEK971 has folding metall buttsock with plastic coating (to protect shooter in extremely hot or cold conditions), plastic forearm and fire control grip, and uses standart AK-47 or AK-74 30rds magazines (depending on chamberings). It also features safety switch/fire mode selector of diferent appearance (when compared to Kalashnikow design). Fire selector allows 2 modes of fire - single shots semi-auto and full auto. At some 800-900 rounds per second it's not impossible to manually control lenght of the fire bursrts, and this weapon is more stable during the fire than ordinal design rifles, so 2 or 3 rounds mode is not implemented (at least, at this time)."

edited to add quotation marks

Originally posted by Essayons

At some 800-900 rounds per second it's not impossible to manually control lenght of the fire bursrts,

You must have much faster reflexes than me, Essayons :D

You must have much faster reflexes than me, Essayons :D

I didn't write that. It's a quote from the linked page. They are probably talking about 5.45x39, which has a smaller recoil impulse than 5.56x45. It may be an exageration, but if the system really eliminates three out four recoil impulses, it might also be true. For example, a lot of the felt recoil in an AR is the buffer slamming against the end of the receiver extension. That's why low mass operating systems can reduce felt recoil (they don't reduce bolt thrust) and make it easier to get the sights back on target.

EDIT: "800-900 rounds per second" appears to be a mistake in the original, linked, text regarding the AEK-971. They must have meant "per minute". The AN-94 Abakan's two-round burst rate is "only" 1800 RPM.

I didn't write that. It's a quote from the linked page. They are probably talking about 5.45x39, which has a smaller recoil impulse than 5.56x45. It may be an exageration, but if the system really eliminates three out four recoil impulses, it might also be true. For example, a lot of the felt recoil in an AR is the buffer slamming against the end of the receiver extension. That's why low mass operating systems can reduce felt recoil (they don't reduce bolt thrust) and make it easier to get the sights back on target.

It wont eliminate the recoil impulses, but it will "delay" (or actually speed up the second shot) the first so much that it wont affect the second shot.

The quote speaks for itself:

"This design is implemented to eliminate 3 of 4 total impulces of the movement that affect rifle during the full-auto fire. 1st impulse rifle received when bullet moves along the barrel - this is recoil itself. Second impulse rifle received when heavy bolt carrier/bolt group moves along the receiver back and forth. Third impulse is received when bolt carrier/bolt group stops in the rear position and fourth - when this group stops in forward position after new cartridge is chambered." LINK (http://world.guns.ru/assault/as34-e.htm) (attributed to the designer, Sergey I. Koksharov)

I see now I should have said "three out of four impulses" (not "three out of four recoil impulses"). My bad.

BTW, this is the AEK-971 and NOT the AN94 Abakan, which has the two round burst that is so fast you only feel the rifle recoil once. They were both developed for the same set of trials.

http://www.marshalarmsinc.com/Products.html

Provided they make it work reliably (never a guarantee when it comes to moving cartridges through off-axis gyrations at typical bolt velocities), the pistol-caliber Marshal should provide a package similar to a P90 in compactness, with the only difference being the orientation and rotation-direction of the ammunition; but it is difficult to see how the (thus far theoretical, AFAICT) 5.56 version can claim to be "compact", since its width can be no less than 2.3" or so--sort of like a light interior-framing stud (right where a shooter would want to rest his chin) with a pistol grip.

...it is difficult to see how the (thus far theoretical, AFAICT) 5.56 version can claim to be "compact", since its width can be no less than 2.3" or so--sort of like a light interior-framing stud (right where a shooter would want to rest his chin) with a pistol grip.

+1 - It would be nice to have some details, particularly where it ejects. Doesn't look like there's room for downward ejection behind the pistol grip. A side-folding stock would address the cheek-weld issue.

Here is some MORE INFROMATION (http://www.military.com/soldiertech/0,14632,Soldiertech_HK,,00.html) on Marshal Arms and (and a bunch of interesting PDW information and links.)

might be using the 20 to 30 degree angle idea that I proposed on this thread. Instead of turning the rounds 90 degrees, you stack them at an angle, similar to the way rounds are stacked in a pistol magazine. Depending on the amount of angle used, you can narrow the magazine to a more managable width...

You know, if I had the money to patent the idea and manufacture it myself, I might be kinda cranky...but they beat me too it.

A bullpup model assault rifle with 18.5 inch barrel in 6.5 grendal. Magazine feed gas piston operated with ability to mount 2x to 4x scopes (acog) directly to the free floated barrel. Left handed shooters should be able to change weapon recoil to left side like French FAMAS assault rifle. Must have a bayonet for crowd control. Overal lenght should be same as famas assault rifle.current m16/m4 flash hider fine but should be modified with teeth for impact weapon capabilitys and crowd control.Chamber and barrel should be chromed for combat in dirty places. Weapon must be torture tested to all the current specs. If I was God this is what U.S. warfighters would be carrying right now :D :D

just make it eject out the front or bottom and you don't have to swap around the ejection port. F2000 ejection tube is an example of front ejection, and the P90 is an example of bottom ejection.

just make it eject out the front or bottom and you don't have to swap around the ejection port. F2000 ejection tube is an example of front ejection, and the P90 is an example of bottom ejection.


I am slowly working on building my own bullpup. I had an Idea I think would have worked for bottom ejection, but the extra length might well have eaten up most of the advantages of a Bullpup.

I have a couple other ideas, but as it will be primarily my own custom hunting rifle, I may just accept Right side ejection. It would certainly simplify things. :D

My only issue with the F2000 forward eject is the lonjevity of the mechanism that guides the spent case into the tube...well that and the possibility of a jam in the tube. Aside from that, I think that may be the way to go.

My only issue with the F2000 forward eject is the lonjevity of the mechanism that guides the spent case into the tube...well that and the possibility of a jam in the tube. Aside from that, I think that may be the way to go.

+1 - After seeing photos of dismantled FS2000s on ARFCOM, I'd prefer to see that component (and the fire control components) fabricated out of metal.

I'd also like to see how the FS2000 would compare to other options - including the M16/M4 in fairly conducted mud, sand and snow tests. Judging from the photos I've seen, it looks like mud/sand/snow could get into the receiver via the cooling slots on the right side or the charging handle slot on the left side and foul things up (reliable ejection amont them).

I heard some complaints about the triggers on the early FS 2000s, but supposedly that's been addressed. I'm sure the FS2000 has a lot of potential - just look at the 50-year history of AR development.

I think the FS2000 has the potential to be a great standard issue weapon. I'm not convinced that the SAW needs to be built on the same platform as the standard infantry weapon. An FS2000 in 6.5 Grendel and a dedicated SAW in 6.5 Grendel would be fine, IMO.

I'm not convinced that the SAW needs to be built on the same platform as the standard infantry weapon.

This is also the conclusion I've reached. The AR and the SAW/LMG/IAR can (and should) be different weapons. Why? Because the SAW/LMG/IAR needs quick-change barrel capability and possibly needs belt-feed.

What is non-negotiable is that both the AR and the SAW, Version I, must feed from the same box and drum magazines. But the SAW should have two versions of an upper that can be easily switched out like the current AR15/M16 system: Version I is magazine-fed (whereby the magazines feed in from the left side) and Version II is a belt-fed upper (like the ARES Shrike).

I'm still not convinced a 100-round belt is that much more useful than a 75-round drum, but absent further data and tactical usage requirements, I guess it should remain as an optional upper.

John

FWIW, it would be highly desireable for the SAW to use the AR mag, but I don't think it's important for the AR to use the SAW drum (so the Beta-C/FS2000 example, above, would be a non-issue). The Army may agree with me. I unerstand they may lose the mag-well on whatever replaces the M249s in service. 6.5 F2000 ARs and Ultimax 100 SAWs with compatible box mags anyone?

BTW Is anyone familiar with the experimental 5.45x39 SAW that feeds from either a belt or an AK74 mag? It looks like a mini-PKMS that will take an AK mag. NIH, but one could do worse than the PKM design.

I'm not convinced that the SAW needs to be built on the same platform as the standard infantry weapon.
This is also the conclusion I've reached. The AR and the SAW/LMG/IAR can (and should) be different weapons. Why? Because the SAW/LMG/IAR needs quick-change barrel capability and possibly needs belt-feed.
The conclusion may be correct, but I think the reasoning is arguable. Judging from history, a QCB does not appear to be truly necessary. A couple of examples of successful non-QCB IARs come readily to mind: the BAR and RPK. Also, these -- and indeed most -- IARs have been magazine-fed, so belt feed does not seem overly critical.

Another characteristic that nearly all IARs have in common is a more robust construction, especially the receiver. This is necessary for adequate durability in full-auto firing. Somebody once pointed out that assault rifle receivers are lacking in this regard.

The conclusion may be correct, but I think the reasoning is arguable. Judging from history, a QCB does not appear to be truly necessary. A couple of examples of successful non-QCB IARs come readily to mind: the BAR and RPK. Also, these -- and indeed most -- IARs have been magazine-fed, so belt feed does not seem overly critical.

Another characteristic that nearly all IARs have in common is a more robust construction, especially the receiver. This is necessary for adequate durability in full-auto firing. Somebody once pointed out that assault rifle receivers are lacking in this regard.

The RPK is supposedly "just" a ruggedized AK...

As I may have mentioned earlier, QCBs are only necessary if the amount of IAR/SAWs in the squad is lacking...

If SHTF, a single barrel should be able to withstand close to 1000rds in a very short window of time... Probably more if some kind of active cooling is used...

One thing which is getting increasingly important as weapons-systems is getting more complex, is to make the weapons more userfriendly and "infantry-proof", to enhance combat-awareness and effectivity.

My only issue with the F2000 forward eject is the lonjevity of the mechanism that guides the spent case into the tube...well that and the possibility of a jam in the tube. Aside from that, I think that may be the way to go.
+1 - After seeing photos of dismantled FS2000s on ARFCOM, I'd prefer to see that component (and the fire control components) fabricated out of metal.

Concur with both. On the ejection note, it's purely speculation, but I'd imagine half a dozen pieces of metal in the vicinity of the barrel, not under any sort of tension or restraint, might introduce some disruptive harmonics that could affect accuracy. Overall, as a bullpup fan, I admire the way in which FN has addressed the principal tactical shortcoming of bullpups, and the reviews on ARFCOM seem overwhelmingly positive. As with any rifle, though, there are a few other minor changes I'd prefer. First, the FS2000 seems to follow (or rather, to epitomize) the trend whereby the designer of a bullpup (a configuration that, in eliminating the buttstock, can eliminate not only most of the stock's length, but also its weight) chooses instead to mold the saved material (or, in the case of the FS, two or three stocks' worth :eek: ) into superfluous plastic trim. On the FS2000, a veritable Pontiac Grand Prix of assault rifles :D , the bulky furniture also prevents insertion of drums and other aftermarket extra-capacity magazines.

Second, the length of pull considered optimum for the average shooter is 13.5 inches (less when wearing body armor and/or web gear). The length of a rifle-caliber bullpup's action may make it impossible to achieve this objective, but positioning the grip as far aft as possible without interfering with magazine insertion helps. The FS2000's mag release button adds an extra inch or more in that area.

The FS2000 is closer to perfect than most, and if they made one in 6.5 I'd be awfully tempted to buy it.

Take care,
Mike

The AR and the SAW/LMG/IAR can (and should) be different weapons. Why? Because the SAW/LMG/IAR needs quick-change barrel capability and possibly needs belt-feed.
While no existing assault rifle meets the belt-fed requirement AFAIK, several do offer QCB (some quicker than others). Approaching the problem from the other direction, neither of these options exclude a SAW from service as an AR. Case in point:

What is non-negotiable is that both the AR and the SAW, Version I, must feed from the same box and drum magazines. But the SAW should have two versions of an upper that can be easily switched out like the current AR15/M16 system: Version I is magazine-fed (whereby the magazines feed in from the left side) and Version II is a belt-fed upper (like the ARES Shrike). Your suggestion for Version II has Version I capability (http://javascript:openNewWindow('shrike2.html', 'Shrike', 'height=593, width=790, toolbars=no, scrollbars=no')), albeit from a conventional AR magwell rather than from the left side (I can't think of any disadvantages there, and the advantages in balance and flexibility are obvious). Of course, the Shrike may be vaporware as of yet, but the HK21 and Stoner 63 also offer belt feeding in an AR-size package.

I'm still not convinced a 100-round belt is that much more useful than a 75-round drum, but absent further data and tactical usage requirements, I guess it should remain as an optional upper.

John
As I may have mentioned earlier, QCBs are only necessary if the amount of IAR/SAWs in the squad is lacking...

If SHTF, a single barrel should be able to withstand close to 1000rds in a very short window of time...
Once you dispense with the belt-fed requirement, of course, you open the field that much farther. I'd keep QCB, though, first of all because it is the least-objectionable solution (at least within the IAR weight envelope) to the barrel-heating problem (versus one, or usually more than one, of the following: an extremely heavy barrel; water cooling; an air-circulating system adding parts, weight, and complexity; or training soldiers to fire short, widely-spaced bursts--as though that's going to happen, or work, if SHTF). A barrel may well be able to withstand 1000 rounds in a short time frame, but cartridges cannot; even on an open-bolt gun, barrel changes are recommended every 250 rounds, and 400 is pushing it. I would assume that an AR/IAR platform will fire from the closed bolt (the inaccuracy inherent in open-bolt firing being the one feature preventing most LMG designs from serious consideration as ARs), making heat management an even more critical consideration.
Equally important is the versatility that QCB offers. Since the AR already incorporates a factory-headspaced barrel extension in the design, a QCB system like MGI's coupled with a rail interface system (included with the MGI upper) and standardization on the Grendel cartridge is a dream come true in terms of logistical and tactical flexibility. Now if only they made it work in a bullpup--but wait:

6.5 F2000 ARs and Ultimax 100 SAWs with compatible box mags anyone?
By the looks of the FS2000's bolt face, it looks as though it extracts and ejects conventionally in AR fashion, then simply redirects the empties down a tube (before seeing the pictures I wondered if it was something more complex, like the wipe extractors on BMGs or Vickers guns). Put the FS system on an Ultimax, stir in a pinch of lightweight polymer construction, two rails of Picatinny (I can't think of anything for which I'd need four, but whatever floats your boat), and a cupful of Grendel, and you have a chassis that becomes an AR, DMR, SAW, or PDW in seconds. Are you listening, Santa?

Merry Christmas,
Mike

The RPK is supposedly "just" a ruggedized AK...
Yes, but the key word there is "ruggedized." As I understand it, the RPK has a receiver made from thicker steel than that of the AKM. The RPK is not just an AKM with a long barrel and bipod.
I would assume that an AR/IAR platform will fire from the closed bolt (the inaccuracy inherent in open-bolt firing being the one feature preventing most LMG designs from serious consideration as ARs)...
I think it depends a lot more on whether or not the IAR has the same configuration as the infantry rifle, as well as whether or not there is aa requirement for firing accurate single-shots (remember, the M1918A2 BAR was open-bolt, and was highly regarded as an IAR).

That's one of the major drawbacks to Colt's M16 LMG, which fires from open bolt. Since the LMG/IAR has the same ergonomics as the M16 rifle, the shooter who's been used to firing the closed-bolt M16 and M4 is highly susceptible to having "accidental" discharges with the open-bolt gun.

If the IAR is completely different from the assault rifle, as in the case of the M249 LMG (and the BAR), the probability of an AD caused by "muscle memory" is far lower.

Once you dispense with the belt-fed requirement, of course, you open the field that much farther. I'd keep QCB, though, first of all because it is the least-objectionable solution (at least within the IAR weight envelope) to the barrel-heating problem (versus one, or usually more than one, of the following: an extremely heavy barrel; water cooling; an air-circulating system adding parts, weight, and complexity; or training soldiers to fire short, widely-spaced bursts--as though that's going to happen, or work, if SHTF). A barrel may well be able to withstand 1000 rounds in a short time frame, but cartridges cannot; even on an open-bolt gun, barrel changes are recommended every 250 rounds, and 400 is pushing it. I would assume that an AR/IAR platform will fire from the closed bolt (the inaccuracy inherent in open-bolt firing being the one feature preventing most LMG designs from serious consideration as ARs), making heat management an even more critical consideration.
Equally important is the versatility that QCB offers. Since the AR already incorporates a factory-headspaced barrel extension in the design, a QCB system like MGI's coupled with a rail interface system (included with the MGI upper) and standardization on the Grendel cartridge is a dream come true in terms of logistical and tactical flexibility.

An IAR could be constructed in a way, so that it fires single shots from a closed bolt, but fires automatic from open bolt... This may require a different kind of safety/selector to be practical, but it could be implemented in both IARs and ARs for familiarity and practicality...

However, a QCB may add some weight to the assembled weapon, as it will need some kind of handle to be practical to change in the middle of a firefight, as well as the weight of the extra barrel itself...
To me, a "quick field-replaceable"-barrel would be preferrable, as you wont have to carry another barrel around all the time, and you save some weight and bulk... If you think you need a QCB, simply add another IAR to the squad instead... It will save you both weight and bulk, and will allow a greater amount of firepower to be available at all times, and disperse the total amount of IAR-ammo on more IARs...

What is the practical maximum designated amount of ammo available to one (of several) IAR in a riflesquad? Probably maximum 1000rds...

If you shoot 1000rds as fast as you can reload and pull the trigger, then you are most likely in very deep trouble, and if you had a QCB, you would have two cooler barrels, but less ammunition... As long as you fire from an open bolt, and as long as you dont have a FTF, the rounds wont cook off...

Some action designs could address the length-of-pull issue. IIRC, coolhand mentioned the Mini-14, and the similar Grarand/M14 and M1 Carbine cations also spring to mind. It would put the magazine very close to the shoulder, though, and would definitely be right-hand-only unless you added a F2000-style ejection system, or made the system top feeding and bottom ejecting (by turning the action upside down). Top feed would raise other issues, but Coolhand has some interesting ideas to that end.

Another solution I like would be something with the general layout of the FG42. It would reduce OAL by about 3". You might be able to feed it from something like a Beta-C mag from above (so the sight line would be immediately above the "top" of the upside-down Beta-C mag), and use something like the F2000 system to eject spent cartridges forward and down through a port immediately ahead of the trigger guard. All that would probably require positionsing the gas system to the side(s). It also wouldn't lend itsel to the use of box magazines (unless you used an offset mag well or offset sights for a "Bren" type configuration)...

Another idea I've been mulling regarding the IAR/SAW is a variation of ABS's carbon-wrapped barrel technology. The jist of the idea is to use carbon-fiber and pitch-impregnated resin to form a monolythic barrel/receiver/chassis. The problem is, ABS's wrapped technology doesn't lend itself to machining, but it suggests the possibility of a very stiff, but reasonably lightweight structure that would radiate heat very well (CF picatinny rails might also double as cooling fins) I don't know if chopped fiber in pitch impregnated resin would offer the same thermal performance. I wish I did.

http://www.iom3.org/materialsworld/feature-pdfs/jul05/Extended%20brief.pdf

The ABS barrel will reportedly shed heat at 365% of the rate of steel - that should take care of the heat and eliminate the QCB requirement given that an IAR needs to stop every 70-100 rounds to reload. The above link provides some info on superplastic forming and having investigated this technogy in some depth for forming a monolithic hull for the PAV it is my opinion that a monolithic Ti receiver can be made fairly cheaply in terms of machining costs. Browning uses this same technology in their Ti A-Bolt. The trick is to use a large, gross thread for the barrel and then provide a plug whose inner surface is machined for the barrel. Inconel or tungsten would both be good choices. It might also be possible to form a Ti receiver with an aluminum inner sheath which extends down (or up for a Bren feed) in an extended mag well which will help stabilize the mag and also acts as a heat sink and cooling fin. I also like the idea of a barrel nut that is scored and drilled for better heat dissipation. (POF ???)

Combining these ideas we might have an inner aluminum sheath that extends ahead of the barrel/receiver junction severel inches and is "fluted" and drilled, comes thickly through the Ti rough "threading", lines the entire receiver, and then extends down to form an extended mag well. A steel barrel plug is then deeply threaded back into the aluminum sheath which is superplastic formed inside the superplastic formed Ti receiver after cooling to the much cooler temps at which aluminum is formed. This would be a novel use of double sheet SPF/DB. It would seem to offer very high strength, low weigh and cheap mfg. Once the process is set up SPF/DB is not significantly different from forming plastics. Plastic guns with metal inserts where needed for wear or heat are already COTS tech.

Originally Posted by Spartiate
I would assume that an AR/IAR platform will fire from the closed bolt (the inaccuracy inherent in open-bolt firing being the one feature preventing most LMG designs from serious consideration as ARs)...

I think it depends a lot more on whether or not the IAR has the same configuration as the infantry rifle . . .
The entire context of my post, not to mention my use of the term "an AR/IAR platform" in the very sentence you quoted, should make it clear that I was, in fact, advocating a dual-use platform or "IAR [in] the same configuration as the infantry rifle". Nipping at the eggnog, Stan? :p

That's one of the major drawbacks to Colt's M16 LMG, which fires from open bolt. Since the LMG/IAR has the same ergonomics as the M16 rifle, the shooter who's been used to firing the closed-bolt M16 and M4 is highly susceptible to having "accidental" discharges with the open-bolt gun.
I wholeheartedly concur.

If the IAR is completely different from the assault rifle, as in the case of the M249 LMG (and the BAR), the probability of an AD caused by "muscle memory" is far lower.
Unfortunately, the need for extensive training in order to safely and effectively employ open-bolt MGs is endemic to that operating system, rather than limited to those resembling ARs. In my experience, people who either grew up with, or were first introduced in boot camp to, closed-bolt semi/full-automatic or manual rifles, pistols, and shotguns find open-bolt operation counterintuitive and have to drill extensively with live and/or dummy ammunition in order to grasp the concept. In every single training evolution I've conducted, and many if not most certification events, at least one drill is downed due to misuse of the M-60, whether failure to engage a target due to failure to fire (bolt forward on an empty chamber when the gunner believes the weapon to be in Condition One); an "inadvertent discharge" (the weapons are, of course, unloaded) due to sending the bolt forward without opening the feed cover in the course of transitioning from Condition One to Three or Four; or simple inability on the part of the gunner to answer basic questions on transitioning between the various conditions of readiness. Of course a primary-duty machinegunner will quickly master his weapon through training, but (given the limited time and ammunition available to cross-train everyone else) the requirement for an LMG that a sonar tech or deck seaman (or, even in the infantry, a radioman or grenadier grabbing a fallen comrade's gun) can safely operate in an emergency makes me incline towards closed-bolt firing.

An IAR could be constructed in a way, so that it fires single shots from a closed bolt, but fires automatic from open bolt... This may require a different kind of safety/selector to be practical, but it could be implemented in both IARs and ARs for familiarity and practicality....
True, and I'm exploring the mechanics of such a firing mechanism myself--but cautiously, since this seems to increase the chances of an inadvertent discharge dramatically. I know the Stoner used separate, swappable trigger groups for the AR and SAW roles; I believe the CETME, or one variant at least, offered both open- and closed-bolt firing, but I'm not sure if it was from one trigger group or swappable units. I would welcome any feedback from anyone familiar with a true single, dual-purpose fire-control group. It would seem to me that the transition from full to semiauto fire would be a high-risk point under stress, requiring the gunner to select semiauto before releasing the bolt forward.

The ABS barrel will reportedly shed heat at 365% of the rate of steel - that should take care of the heat and eliminate the QCB requirement given that an IAR needs to stop every 70-100 rounds to reload.
I'm a carbonfiber fan to begin with, and ABS technology sounds fantastic-- almost too good to be true. It's a shame that, unlike many manufacturers of aftermarket AR parts with potential military applications (like AA and some of the piston operating systems), ABS doesn't seem to have tried their product in full auto on a registered lower. Although their focus seems primarily to be target shooters, a rapid-fire torture test--especially a head-to-head trial conducted by a neutral third party--would seem to be fantastic publicity.

I hope everyone had a terrific Christmas, with plenty of toys under the tree.

Take care,
Mike

The entire context of my post, not to mention my use of the term "an AR/IAR platform" in the very sentence you quoted, should make it clear that I was, in fact, advocating a dual-use platform or "IAR [in] the same configuration as the infantry rifle".
Well, it may have been clear to you...
Nipping at the eggnog, Stan? :p
No. Due to concerns about high cholesterol, I was imbibing nog without the egg. ;) :D
Of course a primary-duty machinegunner will quickly master his weapon through training, but (given the limited time and ammunition available to cross-train everyone else) the requirement for an LMG that a sonar tech or deck seaman (or, even in the infantry, a radioman or grenadier grabbing a fallen comrade's gun) can safely operate in an emergency makes me incline towards closed-bolt firing.
Concur.

It would appear that the answer is a little more complex than "do this and that to get the perfect combination".
While a bullpup would be a benefit due to the longer barrel, it introduces a few issue, some of which have already been mentioned. First is the ability to switch from right to left hand versions. Second issue is that to design a universal weapons system such as the Chinese recently attempted to do with their 5.8mm chambered weapons, would require a conventional AR design - as it is dang near impossible to design a proper LMG on a bullpup design.

My suggestion would be to keep the current M16/M4 platform.
Infantry: M16 with 18.5" piston upper
LMG: Beefed up lower with Shrike (if it happens) upper
DMR: M16 with 20" upper

The M16 platform has proven itself. It is reliable, accurate and modular.

Personally I think that a locked-recoil operated system is the most reliable. Much like the HK G3 - but this system also has its drawbacks :)