Bryan Krueger
The Soviet tanks designers in 1940-41 created a wild variety of concepts for heavy tanks to deal with the rumours of German heavy tank development. The KV-220 was one of the few heavy concepts to be prototyped. The hull was about one metre longer than a standard KV-1, an extra road wheel station was added and the frontal armour was increased to 100mm. Only two were built. One prototype had a turret similar to the KV-1 and mounted a 76mm gun. A second prototype had a turret similar to the KV-2 turret but was shorter and mounted an 85mm F-30. It was to mount a 107mm main gun, but work was abandoned at the start of the war to focus on regular KV production. The lengthened hulls were eventually reequipped with standard KV turrets mounting the 76mm F-32 and lost in fighting around Leningrad. The enlarged KV-220 turret, which retained the experimental 85mm F-30, was installed on a concrete fortification and used as a static defence where it survived the war.