Comparing: T26E4 SuperPershing vs. IS-6

To increase firepower, a new long-barrelled 90-mm gun was mounted on the T26E1 in January 1945. The prototype was designated the T26E4. Development was discontinued in January 1947 due to problems with the gun and the loading mechanism. A total of 25 vehicles had been built by that time, but never entered service.

Plans for this vehicle were drawn up in the construction bureau of the Chelyabinsk Kirov plant from December 1943 to the summer of 1944. Further development and the construction of the first prototype took place at the Uralmash plant. However, the vehicle had no advantages over the other heavy tank designs under consideration, and its armor was seen as inferior to the IS-4 (Object 701), so the IS-6 was not selected for production.