57 mm anti-tank gun M1943 (ZiS-2)

The ZiS-2 (Russian: ЗиС-2) was a Soviet 57-mm anti-tank gun used during World War II. The ZiS-4 was a version of the gun meant to be installed in tanks. ZiS stands for Zavod imeni Stalina (Russian Завод имени Сталина, "Factory named after Stalin"), the official title of Artillery Factory No. 92, which produced the gun first.

Development

In the beginning of 1940 the design office of V. G. Grabin received from the Artillery Department the task to develop a powerful anti-tank gun. The head of this department Marshal Kulik and its subordinates estimated that the use of heavily armored tanks by the USSR in the Winter War didn't go unnoticed in Nazi Germany and would lead to development of similar fighting machines there. There is also a chance that the department was influenced by the German propaganda about the experimental multiturreted "supertank" NbFz. To this vehicle heavier armor was attributed than it actually had. Therefore, Grabin and its office were guided by the characteristics of the domestic heavy tank KV-1 with 40–75 mm armor. In the opinion of developers, the optimal calibre in this case was 57 mm. The velocity and mass of the armor-piercing 57 mm projectile allowed it to attain sufficient kinetic energy to penetrate up to 90 mm of RHA while keeping the gun sufficiently light, mobile and easy to conceal. However the decision also had a downside: this caliber was new to the Red Army, so the manufacturing of the projectiles had to be started from scratch.