IS-2, IS-2m, IS-3 main gun

[Kenny Goodman]

The main gun of these tanks was the 122mm D-25T and I was wondering why the IS-3 uses a 121.9mm with better armor penetration then the others. The first improved version of this gun (the D-25TA) came out with the T-10 in 1950. Ammo for all three (IS-2/2m/3) was also the same until this newer version came out.

[Drake666]

Will in the game the IS-3 is armed with 121.9mm D-25T and has 10 HE and 18 AP rounds.

From looking it up this is what I found.

The semi-automatic 122 mm D-25T main gun was fitted with a muzzle brake.

The rate of fire was about 2-3 shots per minute.

18 high explosive fragmentation rounds and 10 armor piercing rounds.

So you could be right about the gun onless the muzzle brake increases the penatration and the 121.9mm is the real callaber and the 122mm is just a short hand of the name.

[Kenny Goodman]

Hi Drake. The only thing the muzzle brake does is reduce gun recoil and direct the blast to the sides to help with visibility after firing. I went back into the encyclopedia for the game and the IS-2 has a M30 122mm. Historically all IS-2,2m,3,4 where all armed with the same weapon the D-25T. Better AP ammo was available with the D-25TA on the T-10 in 1950. The new ballistic capped round could penetrate 185mm of armor at a 1000 meters vs. 160mm for the old war time round. The big problem with the ammunition was it was 2 parts, hence the slow rate of fire. The Russians used the IS series as more a break through vehicle then a tank slugger. As when going up against infantry and fortifications the 122mm has a great HE round. The 100mm on the SU-100 was actually a better anti-tank round. Able to penetrate 185mm of armor at 1000 meters, this was in 1944. Also being the standard 1 piece round.

[Paul Vebber]

This is cleaned up in version 3...You don;t happen to have any info the ammo types for the M-30 on the early SU-122 do you?

[Drake666]

Will I looked it up in a speedsheet I did up some time back and this is what I got for the SU-122

121.9 mm D-25S gun AMMO: 30
1 x 12.7 mm DShK AAMG AMMO: 250

In May of 1943 it used the new BP-460A HEAT round, before that I could not find anything.

You can find out a little more about the main gun on this page.
http://history.vif2.ru/guns/defin_4.html