In early 1943, Russian troops managed to capture a German Tiger tank, at that time the most powerful tank in the world, and were aware of the differences with their own heavy tanks. Then they started a program to create a vehicle that would be able to deal with guarantees to these machines. The project accelerated even more after the Battle of Kursk, in which, although the Germans suffered a severe punishment, the limitations of the Russian tanks in the face-to-face encounters with the German heavyweights were reflected. It was decided then, to incorporate the 85mm D5-T gun to the new turret created for the new tank “Izdeliye 237” and mount it on the KV-1S heavy tank chassis. This design was known as “Objekt 239” and a prototype was presented in August 1943 before Stalin, who ordered its construction immediately. The new tank would receive the official name of KV-85 and was a fearsome adversary on the battlefield, although it had the misfortune to be manufactured in a short series of only 148 units between September and December of 1943, because it was an interim model until the arrival of the IS heavy tank family.
KV-85 gallery and more info