Production of the »KV with the large turret« at the Leningrad Kirow plant started in November 1940.
The 1940 model differed from the U-0 to U-3 prototypes mainly by the newly shaped turret.
Although lighter than its predecessor, it still weighed 10 tons with 1.36 tons for the barrel of the 152mm 10S howitzer alone.
The howitzer, mainly designed for the destruction of field fortification, nontheless had an armour piercing power of 75mm at one mile distance, enough to knock out any opponent at the time of its development.
However, the KV-2, initially successful in the Russo-Finnish Winter War of 1939/40, proved quite a disappointment against the German troops in 1941.
Technical breakdowns, German air raids or artillery usually ended the battlefield career of the 52-ton giant, while the few survivors served with the Wehrmacht as »KV-II 754(r)«.