Another PDW cartridge

Swedish experimental PDW round
http://www.amkat.se/Experimentammo/experimentammo.html

Swedish experimental PDW round
http://www.amkat.se/Experimentammo/experimentammo.html


Looks similar to the 5.56 MARS

wasn't 7x33 ammo made on old 9x19 machines- they just made it as long as the machine would handle?

still think a 9x23 or a necked down 9x23 to 6 or 6.5mm would make a really good PDW.

later
P

Hmmm . . . can you say .22 Gustafson ? :D

Made me think of 5.56x30 Colt Mars, too.

I'd rather see "optimum" cartridge that burnt all its powder in a short barrel and/or use a bullet that doesn't rely on velocity-dependent fragmentation for lethality. Then you might employ the same weapon with different length barrels as a PDW/SMG (10" to 14") carbine (14" to 18") or rifle (18"+) without unacceptable muzzle blast and flash from the short-barreled version(s). As we were discussing in another thread, you might even employ a "heavy" load in your DMRs and SAWs. (You'd want to make sure they were safe, if not comfortable, to shoot in your PDWs and SMGs, too, though.)

IIRC, one of the problems with the M1 Carbine in WWII and Korea was it was often used as a rifle replacement, rather than a pistol-replacement (PDW) as intended. Seems to me history has repeated itself with the replacement of most M16 rifles with M4 carbines. The complaints about the M1 carbine's and M4 carbine's occasional failure to stop a determined foe sound similar...

I'd rather see "optimum" cartridge that burnt all its powder in a short barrel and/or use a bullet that doesn't rely on velocity-dependent fragmentation for lethality. Then you might employ the same weapon with different length barrels as a PDW/SMG (10" to 14") carbine (14" to 18") or rifle (18"+) without unacceptable muzzle blast and flash from the short-barreled version(s). As we were discussing in another thread, you might even employ a "heavy" load in your DMRs and SAWs.
If it weren't for the DMR and SAW requirement, the 7mm Whisper might be a good choice for short barrels, especially if loaded with the streamlined, 125gr bullet developed for the pre-WWII .276 Pedersen (see photo). The rearward weight bias of that projectile seems like it should make for rapid onset of yaw, and it has sufficient mass that fragmentation might not be necessary for good terminal effects. Two or three years ago, Gary Roberts wrote in Tactical Forums that he planned to do gel tests of .276 Pedersen, but I don't know if that ever came about. :(
IIRC, one of the problems with the M1 Carbine in WWII and Korea was it was often used as a rifle replacement, rather than a pistol-replacement (PDW) as intended.
That's perfectly understandable. The M1 carbine had the major attributes of an assault rifle: compact size, light weight, large magazine capacity, intermediate power ammo. The M1A1 version added a folding stock; with the M2 came full-auto capability and even greater magazine capacity. Why would anybody be surprised that the troops used it as an assault rifle? :D

Are we agreed that a PDW cartridge must also work in a pistol, and thus also within the confines of a magazine within the pistol grip, like the Uzi?

If so, what is the maximum OAL (overall length) to which a PDW cartridge should be limited? The basic limit is the grip size of the average human hand. I'm going to specify a maximum OAL of 40mm, and that's pushing it, requiring a rather thin grip.

John

P.S. After a little search, the FN 5.7x28 has an OAL of 40.5mm, so that sounds about right.

I don't know. The Colt MARS was never intended to be a handgun round, but maybe it doesn't qualify as a PDW. Here's an excerpt from the patent:

The MARS provides a weapons system that will meet all the requirements of a personal defense weapon system for self-defense and emergency force protection or even a close quarters combat capability. This weapon would obsolete the pistol and 9mm submachine guns among the military, special police, and security forces. It is envisioned to replace 80% of the pistols, all submachine guns, and 20% of the rifles/carbines in current inventories. The M16 was designed using a light high velocity bullet to improve probability of hit and lethal capability while decreasing weight and increasing the soldier's ammunition load. The range requirement was 500m and now with the M16 A2 has been increased to 800m. The M16 rifle and its 5.56mm cartridge were designed around bulky extruded Improved Military Rifle (IMR) powder. Later the Army changed to the denser ball powders causing major problems with reliability in combat. The rifle and ball powder had to be re-engineered in a compromise of the original design. The cartridge design and components are critical and drive the design of the gun. In contrast, the MARS weapon and ammunition were designed together.

The MARS cartridge is the center of the concept in developing the revolutionary weapon system of the invention. The MARS cartridge is designed as part of the weapon system and exploits the high energy densities of modern ball powders. It for the first time uses magnum pistol type powders burned at rifle pressures to achieve high rifle velocities in a short rifle barrel. It uses a fast ball powder to achieve 2600 ft/sec with a 55gr full metal jacket projectile in only an 11 inch barrel. The high ballistic coefficient and high velocity result in a higher hit probability limiting the effects of range estimation, wind drift, and moving targets. When the MARS is battlesight zeroed at 200m, the path of the bullet stays within 3 inches of the line of sight. At a range of 250 to 300m, the operator only has to hold slightly higher on the target to achieve a hit. At 300m, the bullet of the system of the invention is capable of penetrating the Army's personal armor system, specifically the KEVLAR.RTM. helmet and vest.

United States Patent 5,827,992 (http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5,827,992.PN.&OS=PN/5,827,992&RS=PN/5,827,992)

I was reading up on KAC's 6x35. It looks like they picked up the ball where Colt left it. The energy at 300 yards (831 ft-lb from a 10-inch barrel) is impressive. Here's an interesting quote from the other board:

15 coldblue :: 5/30/2006 10:21:20 PM EDT


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Originally Posted By GMAN51:
Very interesting weapon, ....But in terms of balistics it doesn't seem to differ very much from the 5.56, it only has an aproximate 5% increse in energy over the 5.56. Since I am totaly unfamiliar with this new round I am sure there is something that I am missing. Any thoughts or help? Thanks.
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Yes, the "math" is very simlar with 5.56, but with 5.56 you have all those negative consequences when firing 20-inch barrel loaded ammo through a bore half that length.
A primary focus of the PDW concept is efficiency in the smallest package.
The first pills we loaded in this case were 5.56, but they did not terminaly perform as well as a 6mm with a little more mass, etc.
Hope this helps.

LINK (http://www.ar15.com/forums/topic.html?b=3&f=118&t=282979&page=1)

The 5.7mm Johnson wasn't too bad either. Its just a touch more powerful than the 5.7 FN (necked 7.62x33mm case VS 5.7x28mm smaller diameter case)

The 5.7mm Johnson wasn't too bad either. Its just a touch more powerful than the 5.7 FN (necked 7.62x33mm case VS 5.7x28mm smaller diameter case)

Hmmm, reading the patent if one didn't know any better the MARS cartridge seems so revolutionary; but Colt really didn't do anything that wildcatters hadn't done before, a shortened 221 FB with a 30 degree shoulder and magnum ball pistol powders have been used in small capacity wildcats for over 40 yrs.

I agree with Grendelizer that a PDW cartridge should also work in a pistol. However, this is not a universal attitude. The Colt MARS is an example of what I'd consider a non-PDW weapon intended for PDW use, and the Army seems to now be looking for a short-barreled carbine for this role.

So what kind of performance could you get out of 7.62x25 brass using magnum handgun ball powders and rifle pressures? I understand you can use 5.56x45 brass to make 7.62x25 that will handle higher pressure than the standard brass. You might be able to use someting like that in 7.62 or smaller in something like a beefed up roller locked CZ pistol.

Better yet, what would happen if you used magnum handgun ball powders at rifle pressures to get 6.5 Grendel performance out of an even shorter case and barrel? (Obviously not a PDW cartridge.)

So what kind of performance could you get out of 7.62x25 brass using magnum handgun ball powders and rifle pressures? I understand you can use 5.56x45 brass to make 7.62x25 that will handle higher pressure than the standard brass. You might be able to use someting like that in 7.62 or smaller in something like a beefed up roller locked CZ pistol.

Better yet, what would happen if you used magnum handgun ball powders at rifle pressures to get 6.5 Grendel performance out of an even shorter case and barrel? (Obviously not a PDW cartridge.)
I've been rolling this idea around in my head for some time. Reeds designed a round based on this idea - used standard 7.62x25 brass though - necked it down to 5.56. I say go for a 6.5x25 round, using .223 brass. It should have plenty power for a PDW and should be a fairly mild recoilling pistol round. You may be able to do a shallow doublestack in the a pistol configuration. Say 13 rounds in a weapon the size of a Glock 17?

Another option would be to neck a 10mm case down to 9 or 6.5mm.

Yet another options would be to simply use .357SIG cartridges. The velocity from a 10" barrel should be significantly higher than from a 4" pistol barrel - it would easily reach out to 100 yards and is already available.

The requirement for a PDW to reach out and be effective out to 300 yards is a bit stupid, IMO. If you want a weapon to perform the same duty as an AR, get a friggin AR, right? Why not just take standard M4's and put 10" barrels on them and use 65Grendel or 5.56 ammunition then?

I have my doubts about the 5.7FN or smaller HK cartridge packing any kind of punch at 300 yards.

The requirement for a PDW to reach out and be effective out to 300 yards is a bit stupid, IMO. If you want a weapon to perform the same duty as an AR, get a friggin AR, right? Why not just take standard M4's and put 10" barrels on them and use 65Grendel or 5.56 ammunition then?

I agree. I think the KAC "PDW" is really a light assault rifle. I bet they just built on Colt's MARS work to come up with something with better terminal performance. Both the weapon and the ammo are marked "TSWG" (www.tswg.gov). I can't find anything about KAC's PDW or the ammo using Google to search TSWG's site, but it seems like the KAC PDW would be a good choice for VIP protection - light, compact, lethal.

I can think of several reasons to use something like KAC's PDW over a 10" AR in a round that is not optimized for a 10" AR. The KAC PDW doesn't generate anything like the muzzle blast or flash of M885 out of a 10" AR. KAC claims it has more muzzle energy than M885 from a 10" barrel and someone from KAC on ARFCOM claimed it has more energy than at 300 yards, as well. It is also lighter and more compact (side folder).

I can't find anything about KAC's PDW or the ammo using Google to search TSWG's site...
I wouldn't expect their site to have such info, if only for security reasons. Gary Johnston has had some trigger time with the KAC PDW, and told me he has an article soon to be in Visier (a German language magazine), and another to be in an upcoming issue of SOF.
...but it seems like the KAC PDW would be a good choice for VIP protection - light, compact, lethal.
I agree, although I don't know if that's a purpose DHS had in mind when they contracted for development of the gun and ammo.
I can think of several reasons to use something like KAC's PDW over a 10" AR in a round that is not optimized for a 10" AR. The KAC PDW doesn't generate anything like the muzzle blast or flash of M885 out of a 10" AR. It has more muzzle energy than M885 from a 10" barrel and someone from KAC on ARFCOM claimed it has more energy than at 300 yards, as well. It is also lighter and more compact (side folder).
Concur with all points, except for the energies claimed on ARFCOM. Muzzle velocity/energy of M855 from a 10.3" barrel is 2560 fps/902 ft-lbs, according to one Army briefing I've seen. This is significantly higher than the 6x35 TSWG's 2425 fps/831 ft-lbs. (I once chronographed M855 Ball from an 8.8" barrel M16K @ slightly over 2400 fps, which gives credence to the Army figure.)

Plus, the lower BC of the 6mm bullet will result in slower downrange velocities/energies than for 5.56mm.

...although I don't know if that's a purpose DHS had in mind when they contracted for development of the gun and ammo.

Pardon my ignorance, who'd DHS? Never mind - Dept of Homeland Security. Duh. :o

Concur with all points, except for the energies claimed on ARFCOM...

Good points. I edited my post above to add "KAC claims..." ;)

I understand that they want a weapon that can be lethal out to 300 yards, but I mean, really, why develop 4 different cartridges for the military's small arms?
I strongly beleive in the KISS prinicple. 1 cartridge for SMG's/PDW's/Pistols and 1 cartridge for AR/DMR/SAW/GPMG.
The smaller cartridge should be small enough to fit into a handgun. In this case, FN really hit it spot on with the 5.7x28. The only thing I'd change with the package is to match the bullet diameter up to match that of my AR/GPMG/DMR calibre. This would simplify barrel blank production thus cutting costs.
We cannot realistically expect a weapon that was designed for close range enounters, to reach out to rifle type ranges.
The guys using the SMG's/PDW's would be in situations where all contacts are at close range. If a helicopter crew gets downed, they should scoot and evade instead of trying to confront the enemy. In most AO's except prairies and desert, they would have terrain to hide their movements and they will not have to engage the enemy at distances past 150 yards. It would be more valuable to them to have a very light weight weapon that uses simple blowback operation and has light weight ammunition.
One way to look at it is to look at the Russians in WW2. They had SMG's using the 7.62x25 cartridge. Regular infantry...and they did a sterling job. Nothing like a high volume of fire to keep heads down while you get out of dodge.
If he has the capability to use the same cartridge in both his handgun and smg/pdw, it adds to the versatility of his weapons systems, right?
A streamlined 6.5mm 100gr bullet going between 1600 and 2000 fps will cut through most military personal soft armor and will be effective to about 150 or 200 yards. I base this on experiences with the 7.62x25Tok cartridge. It is an extremely flat shooting cartridge.
I also mentioned the 357SIG in another post. Giving some additional barrel length for the prepellant to burn, will turn this into a good medium range self defense cartridge. I have not heard of a 357SIG carbine, but I have a friend that hunts deer with his 357mag carbine - out to 100 yards.He has not lost a deer yet.

Good points. That's what the Chinese did with 5.8x42 (ARs, DMRs and GPMGs) and 5.8x21 (handguns, SMGs and PDWs).

I'm not a big fan of PDWs in general. What I like about KAC's interpretation and the Colt Mini Assault Rifle System (MARS) is they are not really PDWs at all. They are assault rifles that are small and light enough for everyone to carry (sort of like the intended role of the Carbine in WWII). Instead of weighing 8 to 10 pounds like most first and second generation assault rifles and many SMGs, however, they weigh around 5 pounds.

Your analogy to Soviet (and German) use of SMGs still stands. Something like the KAC "PDW" would just fill the intended role of the AKs (and StGs) that succeeded the PPSh-41s and PPS-43s (and MP-40s)...

Your analogy to Soviet (and German) use of SMGs still stands. Something like the KAC "PDW" would just fill the intended role of the AKs (and StGs) that succeeded the PPSh-41s and PPS-43s (and MP-40s)...
I agree, but with the light weight of the M4 platform, this becomes more of a grey area, right?
I think I may have found the solution to our answers!
See: http://www.securityarms.com/20010315/galleryfiles/2000/2018.htm

The projectile weight is not quite as high as I'd like, but this would do nicely. It is a true PDW/SMG/Pistol "optimum" cartridge - if the documentation is accurate.

True. My main gripes with the M4 are (1) 5.9 lbs compared to 4.5 pounds for the KAC "PDW", 29.8" OAL (stock retracted) compared to 19.5" OAL (stock folded for the KAC PDW) and ammunition that isn't optimized for a short barrel (muzzle flash/blast). OTOH, the M4 is a "bird in the hand".

I'm thinking the "optimum" AR round and weapon would minimize, if not eliminate, the need for a PDW.

True. My main gripes with the M4 are (1) 5.9 lbs compared to 4.5 pounds for the KAC "PDW", 29.8" OAL (stock retracted) compared to 19.5" OAL (stock folded for the KAC PDW) and ammunition that isn't optimized for a short barrel (muzzle flash/blast). OTOH, the M4 is a "bird in the hand".

I'm thinking the "optimum" AR round and weapon would minimize, if not eliminate, the need for a PDW.
Since the Optimum AR round is to have the same case diameter as the 5.56x45 round, I would suggest doing something like a 5.56x45 case cust down to 21 to 25mm and mounting a 6.5 100gr projectile. This will defenitely improve upon the dismal performance we've seen from the current crop of PDW's.

The optimum AR round would close the gap and at that point, a new round would be more of a pistol round first and a pdw round second.
I personally beleive that an M4 with a piston upper and a COMPLETE" folding stock would fill the niche quite nicely. The requirement of a buffer in the stock of the current DIG system and collapsable stocks (that still leaves a 6" stock behind the receiver, makes the weapon bulky.

how about a 5.56/9x23 weapon then?

there is already a precedent with the 224 BOZ based on the 10mm round.

the 9x23 can push a 147 @ 1300+ fps so if we made 6.5/9x23 pushing a 100 grainer at 1500+ fps from a 5 inch pistol and 18 or 1900+ fps from a 8 or 10 inch SMG/PDW weapon id would be a very effective round out to 200 yards or better for suport, air crew etc personnel

combine that with M4 /AR15 6.5 grendels and single operator 6.5G LMG's/SAW's in combat units.

I know I would prefer a PDW or SMG with 3 x30 round mags on my web gear as a truck driver taking supplies upto the front - vs having a pistol and 2 15 round mags. in case things turned nasty.

just an idea
also the 6.5/9x23 could be built into a 1911 frame and thats got to be a good thing :)

later
P