Comparing: IS-3A vs. Kirovets-1

In 1956–1957, the Military Armored Forces Academy developed a speculative design for a new loading system on the IS-3 and T-10 heavy tanks. The IS-3 variant featured a double-row ammo rack with an automatic loading system. The crew was reduced to three members: commander, gunner, and driver. The turret was redesigned in order to accommodate the loading mechanism. The vehicle existed only in blueprints.

The Kirovets-1 project (IS-3, prototype No. 1) was developed from July through November 1944. The prototype was built at the Chelyabinsk Kirov Plant in September–October 1944. From December 18 through December 24, 1944, the vehicle underwent trials at the NIBT proving grounds in Kubinka. After it was decided to manufacture a pilot series of the modified IS-2 with a hull proposed by engineers of Plant No. 100 and Сentral Research Institute-48, the work on the Kirovets-1 was discontinued.