Author Topic: Balistics question? (Read 363 times)

aknimitz · « **on:** December 17, 2001, 07:23:00 PM »

I'm hoping someone here might be able to help me out. I am looking to find the velocity of the German 20mm vs. the Russian 20mm. I guess more specifically the MG 151/20 vs. the ShVAK and B-20. Thanks

Nim

Tony Williams · « **Reply #1 on:** December 18, 2001, 01:31:00 AM »

The quoted muzzle velocity for both the ShVAK and B-20 was 860 m/s. Projectile weights were within the 91-99g range.

With the MG 151/20 the MV varied a lot depending on the loading. There were basically two projectile weights; HET and API, which weighed in at 115-117g, and high capacity Minengeschoss HE, which weighed 92g. Quoted velocities for these vary according to source, but were around 700 m/s for the heavy projectiles and 800 m/s for the M-Geschoss.

Tony Williams
Author: "Rapid Fire: The development of automatic cannon, heavy machine guns and their ammunition for armies, navies and air forces"
Details on my military gun and ammunition website: http://website.lineone.net/~a_g_williams
Gun and ammunition discussions at: http://www.delphi.com/autogun/messages

aknimitz · « **Reply #2 on:** December 18, 2001, 02:25:00 PM »

Thanks a bunch!

Nim

Hooligan · « **Reply #3 on:** December 18, 2001, 02:26:00 PM »

ShVAK's were apparently made with several different muzzle lengths. As far as I can tell the MV varied between about 750m/s and 860 m/s depending upon projectile weight and muzzle length. What is not clear to me is which versions of the ShVAK were mounted in the various installations on Soviet aircraft.

Hooligan

Vermillion · « **Reply #4 on:** December 18, 2001, 04:31:00 PM »

Plus the B20 and the ShVak were ballistically identical, given a similar barrel length. They used the same ammunition.

Tony Williams · « **Reply #5 on:** December 19, 2001, 02:32:00 AM »

Quote

Originally posted by Hooligan:
ShVAK's were apparently made with several different muzzle lengths. As far as I can tell the MV varied between about 750m/s and 860 m/s depending upon projectile weight and muzzle length. What is not clear to me is which versions of the ShVAK were mounted in the various installations on Soviet aircraft.

Hooligan

The long-barrelled version was fitted into engine mountings, to fire through the airscrew hub. I have never seen any data on how the barrel length affected the muzzle velocity, though - do you have a source?

Tony Williams
Author: "Rapid Fire: The development of automatic cannon, heavy machine guns and their ammunition for armies, navies and air forces"
Details on my military gun and ammunition website: http://website.lineone.net/~a_g_williams
Gun and ammunition discussions at: http://www.delphi.com/autogun/messages