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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.

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PDW again   Small Arms <20mm

Started 20/12/20 by DavidPawley; 40610 views.
smg762

From: smg762

4/1/21

The p90 is 2. 2inch wide. 

Add another 6mm to that with your larger mars round. Even getting in/out a vehicle would be a nightmare. 

If you are desperate to have the ammo away from the grip,  make the gun a tiny bullpup.... Like the magpul PDR. 

or,  give it a normal layout like an MP5. 

the reverse feeding would still keep it very short... use a side folding stock. 

another benefit of 5mm is that you wouldn't need a flash hider.... that saves 1. 5inches. 

As far as ammo performance. You can't realistically aim well,  and expect to hit anything at 300m,  with a 10inch barrel.  Unless your skilled special forces. 

The realistic range would be 200m max. My suggested round would have 830 at the muzzle,  and easily 300ft lbs at 200m.  

With a 47 grain that is highly lethal.  Even 50ft lbs is lethal. 

The MP7 is in a different class... at 200m it would have about 70ft lbs... so you can see my cartridge is a step up. 

basically go with a magpul PDR type gun,  or an MP5 type with no flash hider.

 Reverse feeding malfunctions only apply to handguns... the slide jams if not pulled back very aggressively. 

graylion

From: graylion

4/1/21

5.7x28 has a COAL of 40.5 mm. The round I just proposed has a COAL of 38mm. I have gone away from the MARS round.

And energy alone is not lethal. It needs to actually affect the body, ie get transferred. 5.56 can have lethality issues if it doesn't tumble. A larger calibre is better at that transference.

And what exactly does the barrel length matter with a red dot sight? Sight radius is irrelevant and you v0 is OK. If you can hold the gun steady with a folding stock and a front grip I do not see the issue. The issues that AR15 carbines have are due to a round that doesn't handle short barrels all that well.

And why does the operator error only apply to handguns? You can pull a charging handle too lightly too? Although probably less likely.

BTW can you show me a few calculations for your round? Case capacity etc? Do you have data for the Yaw minimags? I have been unable to find any. Also, with the energy loss you are suggesting you are talking about very significant bullet drop. That will make aiming hard indeed.

you can find an internal ballistics calculator here: http://www.bbt.scot/cgi-bin/pressure.cgi

smg762

From: smg762

4/1/21

With a 38mm OAL the round is barely longer than my 10mm style round... assuming your caliber is 22 or higher you'd need a wide case. 

It's well known that anything above 50ft lbs is lethal so a 300ft lbs bullet is sufficient.  Why add weight and recoil trying to increase that.  

6mm would give you identical retained energy as the 6mm KAC.  This had worse retained energy at 300m than the 22 mars.  And the mars would have worse than a 5mm cartridge. 

With a starting energy of 830,  the 5mm would be almost completely flat at 300m.  The lack of recoil means you could reduce weapon weight by 200-300 grams. 

If you must stick with 22/6mm,  at least use a mini-bullpup,  or mp5 style with reverse feeding.   Far smaller. 

or consider a round like the 6. 5CBJ.  Put the 5mm bullet in a sabot and the ammo size is barely larger then 9mm. 

Then you could make the gun as small as a TMP

graylion

From: graylion

4/1/21

smg762 said:

It's well known that anything above 50ft lbs is lethal so a 300ft lbs bullet is sufficient.  Why add weight and recoil trying to increase that.

It is? Show me some documentation please.

graylion

From: graylion

4/1/21

https://www.ar15.com/forums/armory/With_apologies_in_advance__How_many_foot_pounds_to_stop_a_man_/2-374376/

US Army used to consider 58 ft lbs the minimum to be lethal. That would make a .25 ACP a lethal round. I'm giving up. Whenever I challenge you you dodge, weave and don't provide decent reasoning. kthxbai.

graylion

From: graylion

4/1/21

Missing a folding shoulder stock. 

poliorcetes

From: poliorcetes

4/1/21

Or a pistol brace, or whatever. I cannot realise any serious use of such ridiculously long "two-handed pistol" or "broadpistol"  or zweihander or whatever

graylion

From: graylion

4/1/21

the retro look is rather bizarre.

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