Historical Note: The Kliment Voroshilov (KV) tanks were a series ofSoviet heavy tanks named after the Soviet defense commissar and politician Kliment Voroshilov and used by the Red Army during World War II. The KV series were known for their extremely heavy armour protection during the early part of the war, especially during the first year of the German invasion of theSoviet Union. They were practically immune to the 3.7 cm KwK 36and howitzer-like, short barreled 7.5 cm KwK 37guns mounted, respectively, on the early Panzer IIIand Panzer IV tanks fielded by the invading Germanforces. Until more effective guns were developed by the Germans, the KV-1 was invulnerable to almost any German weapon except the famous 88 mm gun. Even then, its "armor causes hits from the 8.8 cm Flak gun to ricochet." This prompted the Germans to drop development of the VK 20 series and adopt, in great haste, the 7.5 cm KwK 42 gun on a new medium tank design that would become the Panther tank.

Info: Soviet KV-1 Battle Tank Leningrad, 1942