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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-Dec by DavidPawley; 27102 views.
graylion

From: graylion

3-Feb

7.62x25: I'd make the cartridge 1mm longer so it doesn't chamber, increase the COAL, so you can seat bullets further forward and increase the pressure to  440 MPa.

stancrist

From: stancrist

3-Feb

graylion said:

7.62x25: I'd make the cartridge 1mm longer so it doesn't chamber, increase the COAL, so you can seat bullets further forward

I don't know what your concern is with chambering, so I see no need to increase case length.

As for seating the bullet farther forward, the photo of the Chinese subsonic load was just to show 7.62x25 with a spitzer bullet, not to advocate its long projectile.

For maximum propellant volume in a 7.62x25 PDW round, I would suggest a shorter, flat-base bullet similar to below.

gatnerd

From: gatnerd

3-Feb

Sakpan74Gr said:

Would 7.62*25 be a good round for a PDW? If yes, how much barrel length would it need? Could it be used in something like the MP9, or MP7. How about a P90 or an MP5 in that caliber

.30 Luger is drop in compatible with 9x19 firearms, and when loaded to 9mm +p / +p+ pressures, it produces very similar velocities to hot 7.62x25.

https://www.glocktalk.com/threads/17l-varmint-edition-aka-30-luger.1696832/

60gr xtp sized to .309" 1.090" oal:
7.0g PP = 1780fps/422lbs, .387CH
8.0g PP = 1864fps/462lbs, .388CH
9.0g PP = 1900fps/480lbs, .389CH
9.5g PP = 1971fps/517lbs, .390CH

75gr rimrock cast rnfp, sized to .309" 1.090" oal
6.0g PP = 1546fps/397lbs, .387CH
7.0g PP = 1683fps/471lbs, .389CH
8.0g PP = 1730fps/498lbs, .390CH

125gr rimrock cast swc, sized to .309" 1.150" oal
5.0g PP = 1236fps/423lbs, .388CH
5.5g PP = 1284fps/457lbs, .389CH
6.0g PP = 1359fps/512lbs, .390CH

Another load:

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nincomp

From: nincomp

3-Feb

stancrist said...

I don't know what your concern is with chambering, so I see no need to increase case length.

I think that the concern is that civilians would try to chamber the new rounds in old 7.62x25 firearms.  This would only be a problem if the pressure is raised or other specs are changed.

I wonder if Max or some other knowledgeable person could explain why the Soviet Union moved away from this round.

 

edited to correct grammar

  • Edited 03 February 2021 14:51  by  nincomp
graylion

From: graylion

3-Feb

stancrist said:

I don't know what your concern is with chambering, so I see no need to increase case length. As for seating the bullet farther forward, the photo of the Chinese subsonic load was just to show 7.62x25 with a spitzer bullet, not to advocate its long projectile. For maximum propellant volume in a 7.62x25 PDW round, I would suggest a shorter, flat-base bullet similar to below.

Simple. If we increase pressure then I would want to make sure that it cannot be chambered in an old gun. See .460 Rowland.

stancrist

From: stancrist

3-Feb

graylion said:

If we increase pressure then I would want to make sure that it cannot be chambered in an old gun.

What armies still have old 7.62x25 guns in service?

graylion

From: graylion

3-Feb

more civilian market. also, it doesn't make a huge amount of difference and saves the odd civilian casualty, so why not?

stancrist

From: stancrist

3-Feb

Meh.  My view is that if civilians are dumb enough to shoot your super high-pressure ammo in old guns, any casualty they suffer is just Darwin at work.   ;^)

Farmplinker

From: Farmplinker

3-Feb

Or just chamber your PDW in 9x23 Winchester.

17thfabn

From: 17thfabn

3-Feb

"nincomp

I think that the concern is that civilians would try to chamber the new rounds in old 7.62x25 firearms....

I wonder if Max or some other knowledgeable person could explain why the Soviet Union moved away from this round."

I'm no expert. My understanding was the 7.62 x 25 was a fairly powerful for a side arm. Hence it required a strong hand gun action to use it. The 9x18 being a much milder cartridge didn't need as beefy an action to contain it.

Hand guns are probably the least important weapon on the battlefield after bayonets. Switching to 9x18 allowed the Soviets to produce a simpler side arm. 

7.62 x 25 was a good round for submachine guns. With the introduction of  the AK series of weapons the USSR moved away from submachine guns.

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