The 76 mm L-11 tank gun mounted on the KV proved to be ineffective enough to attack bunkers or other fortifications. A new KV-2 tank, equipped with the M-10 152 mm howitzer in the turret, was designed to destroy military defenses. The production of the KV-2 began in 1940. Shortly after the beginning of the Second World War in Russia, however, production was discontinued, as this single-purpose tank was an exorbitant luxury under the severe conditions of the initial phase of the war.
The KV-2 with its 152 mm cannon was one of the most powerful Soviet tanks of the early phase of World War II.