Specification and Armor Penetration of the Soviet Tank Guns

I. Specification

¹ This is the tabular data range.
² The practice rate of fire of the T-34 was 3–5 shots per minute due to unsuccessful ammo layout.
³ The rate of fire during movement didn't exceed 4 shots/min; the ROF in stationary position on motionless target 10 shots/min.
⁴ Initially projected to be single loading ammo, but it was realized to be unsuccessful.

II. armor penetration¹ of the Soviet tank guns

This table is mostly based on data from the NII-48 (Research Lab #48) in 1942–1945. These data are different from widespread penetration data but values presented here seem to me more accurate and often confirmed by after-trials reports. Unfortunately, the armor quality (hardness etc) usually missed in those reports, so I cannot reveal it's real quality. All what was mentioned is «homogenous hardened armor» or simply «homogenous armor» and nothing more.

The tabular data were theoretical and were calculated by method of ARTKOM (Artillery Committee). This method was accepted in 1939 and its final result depended of two values:
— The Limit of the Through Penetration (LTP) when a whole projectile penetrate the armor and was found behind the armor plate.
— The Breaking Point of the Back Surface (BPBS) when a projectile didn't penetrate the armor but the back surface of the armor plate happened to be damaged.

The armor counted to be penetrated if at least 75% of a projectile's fragments happened to be found behind the armor plate. Most of the Soviet armor penetration tables based on this value. Curiously, but the German way of calculation the armor penetration was based on 50% penetration. That's why the Soviet and the German penetration values are so different.

Also, it is important to understand that realistic penetration values in 1941–1943 was reduced significantly due to low quality ammo.

¹ The Initial Penetration (IP) means the 20% probability of armor penetration. The Certified Penetration (CP) means the 80% probability of armor penetration;
² The tabular data.

III. The ammo types used for the tanks and SP guns

¹ In January-February 1941 all these projectiles have been transferred from tanks to regimental field artillery;
² In 1943 this projectile was adding if there was a chance of tank vs tank battle. However, it had poor fuse, so it was quickly removed;
³ Used from summer 1943 only if tank vs tank battle expected. Since 1944 there were 4 rounds in every tank;
⁴ Used from summer 1943 only if antitank mission planned. Since 1944 there were 8 rounds in every SP-gun.