gatnerd

Military Guns and Ammunition

Hosted by gatnerd

This is intended for people interested in the subject of military guns and their ammunition, with emphasis on automatic weapons.

  • 3250
    MEMBERS
  • 184437
    MESSAGES
  • 1
    POSTS TODAY

Discussions

Could a descendant of M193 be a good PDW cartridge?   Ammunition <20mm

Started 24-Jul by poliorcetes; 22245 views.
poliorcetes

From: poliorcetes

24-Jul

M855/SS109 was chosen en 1980 as a substitute for M193 in order to make a cartridge more suitable for SAW use and better behaviour at relatively long ranges. It sacrificed short range performance in order to achieve that.

I was wondering if a new "PDW" cartridge would have enough merits. I mean, a lighter bullet cartridge that could achieve greater Vo and losing it quicker. I was wondering about two variations:

1) a moderate version with the same pressures than M855 and thus fully compatible with rifles intended to use M855. It would sacrifice barrel twist rate since it would be optimized for M855, but at short distances it would be a minor issue

2) a more radical version, with pressures comparable to M855A1 and thus capable of achieve more Vo with 14" barrels. Instead of a long bullet with a steel core, a short bullet with steel core base and plastic core tip.

IF I'm right, it would achieve AGILE-like results at short distances (the distances a PDW is supposedly be used): higher incapacitation probabilities per impact

What do you think¿?

stancrist

From: stancrist

24-Jul

Are you asking about something like this?

I don't know if it would give the severe wound trauma that you apparently want.

A major reason for the damage inflicted by M193 is the explosive fragmentation.

Unlike the lead core of M193, the steel core of your proposed PDW bullet would not fragment.

poliorcetes

From: poliorcetes

24-Jul

It was just another gedankenexperiment by association. I was thinking in avoiding increasing Eo, avoiding lead use in the core, and avoid any kind of restriction caused by the use of the cartridge in a SAW. IF M1186 is adopted by DoD and in Europe, then SAW will use it, combat rifle will use it and 5.56 will be used by second-line operators and as a PDW. 

Besides, M855A1 is not acceptable for most if not all European armies because of Geneva convention. Emeric talked about it time ago. Therefore, SAW-optimized SS-109 would be used in Europe for PDW-like carabines after, say, 2035

Now, if core cannot be exposed and a complete cuproniquel jacket covers the core, maybe if a small, M193-sized bullet has a core made by a steel base and a plastic point would weight something like 30 grain or so and it would be possible to have a Vo of more than 1050 m/s.  Such velocity would produce sizeable temporary cavity and there would be a meaningful probability of jacket rupturing without the devastating effects of lead core fragments. Something like this, without so many mangling tiny fragments but with 2-4 different trajectories at best or even without fragmenting but producing a bigger temporary cavity and thus higher incapacitation probability. A quite better performance at short distance, without explosive fragmentation effects and sacrificing effective range to, say, 200 m at best.

although designs like M855 or our CETME 7,92x40 are controversial, since "jacket" don't necessarily apply as jacket doesn't cover the base and then maybe it would be a ribbon or even a non-discardable sabot that surrounds a monolithic bullet under a legal point of view. When 7,92 CETME was offered to nato, the problem was political stance of Spain during dictatorship, something that those "friendly" belgians leveraged happily. Now it would not be necessarily the case, specially if a new cartridge is produced on a multinational effort

Multinational. Yeah, right...

Farmplinker

From: Farmplinker

24-Jul

Or maybe Johnson 5.7 Spitfire 2.0? Necked down .30 Carbine (7.62x33) to .224 (5.56x33) with a light, high velocity bullet. 

Say 45-grain steel core empty tip at 940m/s? Good up close, but it would be effective range limited.

poliorcetes

From: poliorcetes

24-Jul

Thanks, that's the main concept but looking for less mass and more velocity.

I'm even thinking about what supression and subjective identification of a weapon means. That is inside my full expertise, and obviously I'm inspired in Emeric's results.

European PDW cartridges were defined for penetrating old PacVar crisat armours while maintaining a controllable recoil. Possibly, if such cartridges were used en masse, the adversaries wouldn't fear them very much in hands of non-expert users.

However, it one adversary is shoot using a neospitfire and exit wound is quite volcanic and shocking, and ice picking holes are improbable, and just one or a pair of hits makes the target drop, then a secondary experiential factor would appear.  

stancrist

From: stancrist

24-Jul

poliorcetes said:

M855A1 is not acceptable for most if not all European armies because of Geneva convention. Emeric talked about it time ago. Therefore, SAW-optimized SS-109 would be used in Europe for PDW-like carabines after, say, 2035

Now, if core cannot be exposed and a complete cuproniquel jacket covers the core, maybe if a small, M193-sized bullet has a core made by a steel base and a plastic point would weight something like 30 grain or so and it would be possible to have a Vo of more than 1050 m/s.  Such velocity would produce sizeable temporary cavity and there would be a meaningful probability of jacket rupturing without the devastating effects of lead core fragments. Something like this, without so many mangling tiny fragments but with 2-4 different trajectories at best or even without fragmenting but producing a bigger temporary cavity and thus higher incapacitation probability.

a.  Would a bullet which is designed to break into 2-4 pieces be acceptable to European armies?  As I recall, the UK redesigned their 5.56mm FMJ bullets -- by using thicker jackets -- specifically to prevent the type of fragmentation that you wish to intentionally achieve.

b.  I'm not sure if your proposed PDW bullet -- which I estimate would weigh 30-35 grains configured as in the drawing -- would break apart as you desire.  Note that M193 breaks at the cannelure, but that weak point is reinforced by the steel core on the PDW bullet.

Understand, I'm not saying that it's a bad idea or that it would not work as you expect, because I don't know.  I just have some doubts that it would be significantly better than SS109/M855.  However, it would be interesting to see such a load developed, and comparison tested versus SS109/M855.

poliorcetes

From: poliorcetes

24-Jul

Indeed, JHP 9mm in Europe is not as widespread as in America.

a) OTOH, the problem with bullet fragmentation could be the number and trazability of such fragments. A lot of tiny lead fragments produce a really nasty wound that it's quite difficult to clean. Maybe if there are 2-4 and the materials are copper and steel it would be different.

b) invert the core proportions: one third steel, two thirds polymer. If terminal velocity is close to 1000 m/s, tumbling could break the jacket even without such cannelure. Of course, we are talking all the time about probabilities. IF spoontip is recovered and tumbling happens more frequently, earlier and more violently, maybe cannelure effect would be even surpassed in order to produce the desired effects

What I am entertaining is the possibility of using legacy AR in order to maximize terminal effects maintaining or even reducing recoil

QuintusO

From: QuintusO

24-Jul

How would any of the projectiles you've proposed be "descendants" of M193 if they have nothing in common with it?

You're emphasizing lower mass and higher velocity than M855A1, but why? Mass and velocity ought to be servants of performance, not the other way around. Nothing you've mentioned appears to actually get you more performance, in fact you're explicitly speaking in terms of less performance (appeasing hagueified countries like the UK).

I'm honestly just not seeing the idea here. You're asking for another 5.56 round, but it doesn't seem like you know what you're trying to do or how to get there.

JPeelen

From: JPeelen

24-Jul

Answer to your question a:

Within NATO (with the exception of  the U.S.) the view is that bullets which easily deform in the human body are not in accordance with the law of war as generally accepted. 

Apart from the legal situation, the real problem in my view is that proponents of deformation/fragmenting bullets believe in a more rapid incapacitation, whatever part of the enemy is hit. As a matter of fact, the projectile impact location(!) is the only parameter that governs  rapidity of target incapacitation. Unless a relatively small area of the skull is hit, nothing can be predicted.       

TOP