Optimizing Mil. Ammo

I recently read a Eugene Stoner quote in one of the Black Rifle books. The short of it was he was amazed we were still using M193 when he wrote. He found it "inconceivable" that the first attempt would yield the optimal result. That (and the ideal AR thread) got me thinking...what if you applied the concepts of Optimal Charge Weight (OCW) (http://home.earthlink.net/~dannewberry/index.html) and Optimal Game Weight (OGW) (http://www.biggameinfo.com/OptGameWgt.aspx) to military ammo.

As I understand it, a good OCW round will minimize dispersion in a variety of barrels (a good thing in an Army with M4s, M16s and M249s).

(OGW) (http://www.biggameinfo.com/OptGameWgt.aspx) is supposed to predict the killing power of big game rounds. The following is from the linked page:

"Many authors have attempted to come up with an objective method of determining the "Killing power" of cartridge loadings. This is one that actually makes sense. It differentiates light bullet energies and heavy bullet energies with a degree of rationale I've not found in other systems. It produces numbers that most experienced hunters will find intuitively correct, expressed in a form that is convenient for the hunter, optimum game weigt in pounds. The weight calculated assumes that occassionally you will take a hard quartering shot. If you push the envelope, the author suggests that you choose a load that will deliver a 25% heavier rating. This alsobassumes that the bullet chosen is constructed appropriately for the game being hunted."

I don't think OGW would work unmodified for FMJ ammo, but I bet it could be tweaked to predict penetration and fragmentation in armored and unarmored adversaries.

I think these two concepts would be useful in coming up with the ideal assault rifle round.

I'm not knocking 6.5 Grendel here - I'm sold - but it was developed within certain form factor requirements (had to fit in an M16/AR15 mag well). If you were designing a new system from the ground up (or even an evolution of the old system like MGI Military's modular lower), then you would not be subject to that limitation.

Essayons

P.S. If you follow the link from the OGW page to the Ballistics Calculator (which also calculates OGW) you will see 6.5 Grendel looks great for deer. But then we allready know it works well on deer :D

Good Post,

One of the things that you have to look at from a militar perspective was the history of where we are today.

The 7.62 NATO. Effective power for engaging targets out to 800 meters give or take. Ammunition Weight an issue as well as recoil from rifles required to fire full automatic.

The 5.56 NATO. Effective at short range. Very nice ammunition weight and low recoil for full automatic fire.

The Grendel falls in the middle of these two cartridges as far as ammo weight and recoil and achieves the range performance of the 7.62 due to projectile efficiency. However, it was designed with "here is the box, it must fit in the box" requirements.

The question becomes is a gain in knockdown power over the Grendel worth a gain in weight or recoil? There has been ideas bounced around of going to a 2.500 OAL vs a 2.25 OAL and what impact that would have on all the factors. In fact, Dr Bill Davis and Dr Lou Palmisano did work in 1984 on 1.5", 1.75" and 2" PPC cases. The 1.5" is the PPC standard known today, but the 1.75" holds promise for below. A 2 inch case take the round over the 2.500" OAL requirement.

Looking at some of long seated 130 grain Grendel rounds (2.440" OAL), I wonder what the opportunity would be with those with a slightly longer case with the bullet seated back in the case. I would have to do some analysis to see if the case was this long and the bullet was shoved back in the case, what would the real gain in power capacity be. Not to mention, what would the increase in platform weight be to accomodate 2.5" OAL rounds.

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I have not spent a lot of time studying the OGW formula but it would appear that the base is proportional to the multiplier of the energy and the momentum. Given such a basis the numbers produced will certainly have some bearing in the performance of the cartridge but as with may such formulii it must be considered carefully. The system assumes that the bullet is correctly constructed and performs ideally for the impact velocity at any given range, ie the penetration depth is optimum.

I have not spent a lot of time studying the OGW formula but it would appear that the base is proportional to the multiplier of the energy and the momentum. Given such a basis the numbers produced will certainly have some bearing in the performance of the cartridge but as with may such formulii it must be considered carefully. The system assumes that the bullet is correctly constructed and performs ideally for the impact velocity at any given range, ie the penetration depth is optimum.


If we want to optimize bullets for military use, I find the "CETME" developed bullets and the "Loffelspitz"(sp?) desiged iirc by Dr. Voss fascinating. EXTREMELY well shaped, long for caliber, lightweight (aluminum or plastic cores)
With a very light point and heavier base, they tended to tumble. Given their long length, they caused rather severe wounding as they tumbled. Because they were lightweight, they had low recoil. Because they were very "fine" in shape, they should have been fairly ballistically efficient despite the light weight. They worked with a 7.92 and also a version in 7.62x51(105gr at about 25-2600fps,iirc)


The Loffelspitz, or "Spoon Tip" caused the bullets to tumble even faster.


The guns would have required very fast twist barrels, but the big problem was probably that they weren't the US designed favorites.

I was thinking an 85 grain (maybe) bullet with a very fine form factor that could be loaded (just barely) into a 5.56 length magazine in the Grendel. It might end up even lighter at that length. Assuming that the formfactor for such a fine boattailed bullet would probably be around 2 (yes, it IS and assumption) I get a BC of somewhere around .348
Basing it on the calculated form factors of Hornady A-max bullets
based on 140 gr. .264 Amax I get .3306, based on the form factor of the >50 caliber 750 gr A-max (calculated at 2.5!) I get a BC of .444

It should be simple to drive that weight of bullet nearly 3000 fps, with moderate recoil.

Gewing,

Any URL links we can pour over :D?

Perhaps one could avoid the asymetrical weight - very substantial spinning at 350,000 rpms - by twisting the spoon into an auger. This should make it tuble like mad and really dig in after tumbling 180 degrees base forward as the twist would then be wrong.

Gewing,

Any URL links we can pour over :D?

Perhaps one could avoid the asymetrical weight - very substantial spinning at 350,000 rpms - by twisting the spoon into an auger. This should make it tuble like mad and really dig in after tumbling 180 degrees base forward as the twist would then be wrong.



This is a short article with a picture further down the page that shows some of the designs tested. Tony has several good books out.

http://www.quarry.nildram.co.uk/Assault.htm

Any URL links we can pour over :D?


Go to my 5.56mm timeline, and search for Voss. I have links to a couple of his asymmetric projectile patents.

Thanks for the link DW :D

It occured to me that a drill bit, which uses two symmetrical auger twists, is both about the right twist for a 1:7-8 twist bullet AND balanced. It would have the added benefit of reducing drag while reinforcing the spin/forward motion ratio in flight. This could be especially important when making the transition from supersonic to subsonic. It should be trivial to make such a bullet out of solid copper with any simple lathe. My guess is that such a bullet would tumble in many different directions, not just along the same axis as is normally the case.

PS: Someone was asking about a method for estimating the number of rounds in a mag. Would an AAA battery cell give a good aprox?

If we want to optimize bullets for military use, I find the "CETME" developed bullets and the "Loffelspitz"(sp?) desiged iirc by Dr. Voss fascinating. EXTREMELY well shaped, long for caliber, lightweight (aluminum or plastic cores).
The Loffelspitz never impressed me much. Except for the unique tip, it appears to be a rather ordinary, tangent ogive design. However, I too was fascinated by the ultra-streamlined CETME bullets -- and the very similar FABRL (Frankford Arsenal/Ballistic Research Lab.) projectiles -- when I first read about them. It seemed like an elegant method of achieving low recoil without giving up effective range.

Unfortunately, it turns out there are some critical drawbacks to the design, which are seldom (if ever) noted in writings on the subject. One is that the plastic core used in the FABRL and 7.62x51 CETME bullets violate international agreements on using material that is not easily visible in X-ray photos. With the 5.56mm FABRL bullets, terminal ballistics (specifically, steel helmet penetration at 800-plus meters) were never achieved, primarily because of the bullets light weight. Also, the FABRL bullet made a very poor tracer, a facet that would almost certainly apply to the CETME design. Then, too, there is the probable higher production cost of manufacturing the CETME bullet with its machined aluminum core.

Trivia: One aspect that I've never read about is that since the aluminum core of the early CETME bullets is exposed at the nose, it would almost certainly produce a bit of incendiary effect upon impact with metal targets. I base this conclusion on shooting Winchester Silvertip handgun ammo, which has (or had, back when I was testing the stuff) aluminum jackets in some calibers. When the aluminum jacketed Silvertips hit steel targets, it nearly always produced a brilliant white flash, just like military incendiary ammo (except on a smaller scale).

Yeah, the Loffelspitz seemed a little less interesting than the basic design.

I suspect that the techniques/equipment Barnes uses to create its x-bullets and solids could work with certain aluminum alloys. If you made the bullet similar to a triple shock X-bullet, then swaged a steel penetrator inside of it(not extending to the actual tip, preferably, for better unbalancing) then plated the whole thing with copper....

It is possible that just making it out of aluminum then plating it would work.

I don't know enough to say whether the effective BC would really be adequate to make up for the light weight.

Drilling the base of the aluminum bullet for a tracer should be only a little more expensive. I think tracer compound is about the same weight as aluminum, iirc HE is...



Screw machines and CAd Cam are your friends. :)









The Loffelspitz never impressed me much. Except for the unique tip, it appears to be a rather ordinary, tangent ogive design. However, I too was fascinated by the ultra-streamlined CETME bullets -- and the very similar FABRL (Frankford Arsenal/Ballistic Research Lab.) projectiles -- when I first read about them. It seemed like an elegant method of achieving low recoil without giving up effective range.

Unfortunately, it turns out there are some critical drawbacks to the design, which are seldom (if ever) noted in writings on the subject. One is that the plastic core used in the FABRL and 7.62x51 CETME bullets violate international agreements on using material that is not easily visible in X-ray photos. With the 5.56mm FABRL bullets, terminal ballistics (specifically, steel helmet penetration at 800-plus meters) were never achieved, primarily because of the bullets light weight. Also, the FABRL bullet made a very poor tracer, a facet that would almost certainly apply to the CETME design. Then, too, there is the probable higher production cost of manufacturing the CETME bullet with its machined aluminum core.

Trivia: One aspect that I've never read about is that since the aluminum core of the early CETME bullets is exposed at the nose, it would almost certainly produce a bit of incendiary effect upon impact with metal targets. I base this conclusion on shooting Winchester Silvertip handgun ammo, which has (or had, back when I was testing the stuff) aluminum jackets in some calibers. When the aluminum jacketed Silvertips hit steel targets, it nearly always produced a brilliant white flash, just like military incendiary ammo (except on a smaller scale).

About 10 years ago the Japanese spent a lot of money on their super metals project in an effort to push the envelope on metal technology. One of the outcomes of this research is a commercial - Toshiba is the primary vendor - implementation of hot liquid metal injection molding. This technology is now used to make things like BMW's transmission housings and the process is said to be virtually free of voids and with elasticity very close to solid billet machined parts at a fraction of the cost.

Using this technology it may well be possible to fabricate bullets of substantial complexity for a very low cost. If anyone has an interest in this technology send me a PM and I will give you a good contact you can pursue this with who has this and other related technologies to make real-world production items.

PS: If anyone else is interested in heavier than lead bullets and is looking for a source of tungsten try your local tire dealer. The studs in studded snow tires are made of tungsten and are already fabricated to about the right dimensions. Tungsten is VERY, VERY hard to machine - as it is the metal that most machine tools are made of - so having something of about the right size is very handy indeed. Tungsten is 240% of the weight of steel and 145% of the weight of lead. A 145 grain 6.5 bullet made entirely of tungsten (not practical as it would destroy the barrel) could occupy the same space as a 100 grain bullet and not intrude on the powder in the case. You can see the attraction. Using tungsten cored lead or copper bullet however could produce a 140-150 grain bullet in the shape of a 120 grain bullet with a very VLD profile.

http://www.wtec.org/loyola/welcome.htm
http://www.wtec.org/loyola/casting/00_es.htm

Hmmm . . . could you electroplate a precision cast (or machined) tungsten bullet with copper to protect the bore?

You can also get tungsten powder from some of the swaged bullet sited to make bullets. Sintering tungsten with copper or another metal inside a jacket would give you the benefit of tungsten's mass, but might still be designed to fragment when it yaws in a soft target.