76-mm tank gun L-11, mounted on KV, didn't prove to be suffi ciently powerful to fi ght Pillboxes and other fortifi cations. A new KV-2 tank, fi tted with the M-10 152-mm howitzer in the turret, was designed for the destruction of defensive military fortifi cations. The production of the KV-2s started in 1940 and soon after the start of WWII in Russia the production of the vehicles was phased out as this single-purpose tank was an exorbitant luxury in the severe conditions of the initial period.