The IS-7 (ИC-7), starting life under the project title of Object 260 (объект 260), followed on from the ill-fated IS-5 (Object 730) and IS-6 (Object 252/253). With these failures, the request was still standing for the USSR’s next heavy tank.

The IS-7 was the brain-child of the Soviet tank designer Nikolai Fedorovich Shashmurin. As well as having a hand in the design of the rather successful IS-2 which would serve well in the later years of World War II, Shashmurin also drew up plans for the ill-fated KV-4 (Object 906) project, which never came to fruition.

The IS-7 would be Shashmurin’s crowning glory and could be considered the zenith of the Iosif Stalin heavy tanks. At the time of its conception, it was one of the most technologically advanced heavy tanks in the world, and one of the most heavily armored.

The seeds of the IS-7 were first sown in December 1945 in Factory No. 100 in Leningrad, with a full-scale wooden mock-up produced soon after. Running prototypes were ready for testing in 1946. These tests ran through 1947, ending in 1948 when the designers believed they had reached a finalized design. It was then given the title of IS-7. This final design was armed with a stabilized 130 mm (5.12 in) cannon fed by an autoloader, a total of 8 machine guns, infrared scopes, and armor up to 300 mm (11.8 in) thick. It was the largest tank that the USSR had or would ever produce.

The tank was designed to withstand the impact of a shell fired by the 12.8 cm Pak 44 Gun found on the German Jagdtiger. The armor on the IS-7 was up to 300 mm (11.8 in) thick, some of the thickest being found on the specific pike nose, formed from homogenous steel. The upper plates were 150 mm (5.9 in) thick angled at 60 degrees. The lower glacis 100-120 mm (3.94-4.72 in) with a slight angle.
The side armor was also not to be underestimated. The upper hull was 150 mm (5.9 in) thick, while the lower sides measured 100 mm (3.94 in) and was curved outwards, meeting the upper hull seamlessly. The bending of the lower hull was done in a large press, which literally forced the metal into shape.