gatnerd

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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NGSW evaluation update   Small Arms <20mm

Started 31/7/20 by autogun; 16074 views.
gatnerd

From: gatnerd

6/2/21

JesseH1234 said:

7.62x51 is already losing a fair bit of velocity shooting out of a 16" barrel.  Cranking the pressure to 80k psi means you are probably losing a crapton of velocity out of a 16" barrel.

Per the SIG 6.8 Briefing awhile back:

SIG Rifle 13" = 2850fps

SIG LMG 16" = 3000fps 

A pretty big bump in velocity for 3"; +50fps per inch. 

Assuming that held true, we'd expect 3200fps from a 20" barrel. Probably closer to 3150fps as velocity increase would likely get lower as barrel length increases due to drop off in bore pressure.

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