Military Guns and Ammunition

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This is intended for people interested in the subject of military guns and their ammunition, with emphasis on automatic weapons, particularly in larger calibres (12.7+mm).

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Exploring The Design Space   Ammunition <20mm

Started 25/7/15 by NathanielF; 99546 views.

From: QuintusO


Also we do have a competition coming up, that being the reboot of the Texas Truck comp.


From: EmericD


Gripen287 said:

.230 Theriac is also similar to what you're describing. It's a 77 grain EPR with a steel penetrator, steel core, and a .236" integral driving band diameter. The case has a .42" rim diameter and a 1.685" stainless steel case with polymer cap. COAL is 2.5".

I dunno why relaxed, but I really like this one...

I didn't thought about it when I made my first "neckless" rounds, but this geometry could reduce the complexity of making thin walled steel case, and also allowed for an easy "100% load density" of any cartridge, because it's easy to adapt the shape of the polymer cap to remove any unwanted ullage.

Did you ever try to compute the dynamic stability of your 6 cal long bullet?


From: alexsoddy


Dear Mr. @QuintusO,

As you might know, the Indian Army(called IA from here on) is planning to discard its current service rifle cartridge and adopt the 7.62x39 mm Soviet. The IA is currently using a non-standard cartridge based on 5.56 NATO - its COAL is 0.009 inches longer than that of 5.56 NATO.

This transition will mean that a solider can carry fewer rounds than before. But the IA is fine with this penalty as long as the new round promises greater stopping power. Also, the front-line infantry will be armed with 7.62x51mm NATO (IA already bought SIG 716s for them). So the new round will be used by the rest of the soldiers and also for counter-insurgency. Do you think it is a good idea to adopt the 7.62x39 mm Soviet in this day and age ? Or does an alternative general purpose round exist ? The decision to discard the current 5.56 mm cartridge has already been taken. Only the question of a suitable replacement is up for debate.

The general purpose round that they desire needs to :-

1.) Kill or grievously injure at ranges greater than or equal to the maximum effective range of 7.62x39 mm Soviet when fired from 16.3 inch barrels.

2.) Have recoil velocity and energy comparable to the 7.62 Soviet fired from an AKM.

3.) Have cartridge weight comparable to the 7.62x39 mm Soviet.

4.) Be as inexpensive as the M855 or 7.62x39 mm Soviet cartridges.

There are no other restrictions (COAL, case head diameter etc.) because IA is prepared to adopt a new rifle anyway. But increasing the COAL too much maybe undesirable because of the increase in rifle weight.

Do you have any suggestions ?

(Some would argue that adopting the M855A1 or Mk318 rounds is a better solution. But many in the IA don't want to discuss the 5.56x45 mm cartridge anymore.)


From: Red7272


There isn't a lot of reasoning being applied to the process. Their old round was 7.62x39 and they are fine sticking with that. It also makes buying external weapons and ammunition simpler. The 7N23 or a local faster yawing projectile are possibilities. If the round is not expected to be effective beyond 400 metres then there are not a lot of alternatives other than 5.45. That would be a new calibre and make the replacement of the INAS harder to explain. They can lie and say the 7.62x39 has greater lethality and no one will dispute the change. Increasing the OAL again to allow a better projectile form again would be a good option, but the round is entirely workable as is. 


From: QuintusO


I agree with Red that I think the Indian Army is using 7.62x39 as an excuse to procure a different rifle than the INSAS. There may also be some complaints about the effectiveness of 5.56x45 INSAS, but I doubt that is the overriding concern.

7.62x39 is not a very good rifle caliber by today's standards. It is fairly small and lightweight, but it does not offer as favorable performance as other designs. It suffers poor drop and drift, and its lethality in FMJ format is among the worst of any military rifle caliber still in widespread use (including 5.56). Only .30 Carbine M1 Ball and 7.92x33 Kz.Ptr.SmE 43 are inferior, among military rifle calibers. 

However, from what I understand, India only has in service three rifle calibers: 5.56 INSAS, 7.62x39, and 7.62x51. This substantially limits their options, and if neither of the other two are deemed acceptable, then 7.62x39 is the default.

Other calibers do exist, there's the 5.45x39 and 5.8x42, and the 6.5x38 in limited service with Serbia. But it does not sound like the Indian services are interested in a caliber other than 7.62x39.

Ultimately, the Indian defense machine is very likely to do whatever enriches itself, and not whatever is best for the soldier. That's how they got decades of the INSAS, and I don't see that cycle stoping now.


From: alexsoddy


Do you think Mitch Shoffner's 6.5x40 cartridge (based on the SPC case) is superior to the 7.62x39 mm Soviet ? And should the IA consider it ?

If not the 6.5x40, would the 6x44 mm cartridge(that you designed) be a good successor to the 7.62x39 mm ?

I attach an excerpt from an article written by a Lt. Gen in the IA. This perhaps seems to be summarize why IA doesn't like the 5.56x45 mm cartridge.  Source:


From: roguetechie


While in theory that story "could happen" under some very weird and freakish circumstances I'm still going to outright call bullshit.

That general is straight up "making shit up".

Beings as India is very unlikely to buy actual good 7.62x39, you guys are probably looking at warmed over m43 rounds at best which have been known to have inferior lethality and true effective range compared to 5.56 since Vietnam.

Actually buying 5.56 ammo that's better than m855 is probably the best answer for the IA since modern 5.56 is more than capable at 500 meters plus from a 16" barrel. 5.45 would also give this kinda range and performance (again provided you bought good ammunition).

As has already been said, 7.62x39 is Virtually the worst choice you can make and no amount of wildly implausible stories from generals will change that.


From: QuintusO


There is no military spec for the 6.5 Schoffner. You might as well design an entirely new round.

India will go with 7.62x39. That may not be the smart thing to do, but I don't have a lot of faith that there are any alternatives. Maybe I'm wrong, I'm not an Indian dompol expert.


From: QuintusO


Like unless you have some special insider knowledge, their minds appear to be made up already. Those who might object are probably ready to accept anything to make the pain of INSAS stop.


From: alexsoddy


Yes, you are correct in your analysis. The primary motivation seems to be to keep out any product made by the socialist factories. Other concerns are secondary.

A private company named SSS Defence hopes to jump in with its product in case the AK-203 deal collapses. It has been reported that the Russians are demanding a royalty of $200 for every AK 203 produced in India. This seems to be a deal breaker.

More about the product from SSS Defence: