KV-6 Soviet Heavy SPG

In order to increase the firepower of tank units and provide equivalent tank mobility of SPG, heavy SPG KV-6 on the basis of KV-1 was developed. Armament consisted of 3 triple-guns: two 45mm cannons and one 76mm cannon. The vehicle testing passed in December 1941. Fire tests indicated the inadequacy of that gun-system structure to be installed in combat vehicles.