Comparing: AT 15 vs. ISU-130

Assault tank conceived to break through fortified positions. The design project was ready by the fall of 1943, but no prototypes were manufactured. However, the project became the basis for the A39 Tortoise heavy assault tank.

This heavy SPG on the basis of the ISU-122S was developed in 1944, with a prototype built in October. The 130-mm S-26 gun, based on the B-13 naval gun, was mounted on the ISU-122S. The vehicle underwent automotive and firing trials by 1945, but penetration characteristics were inferior to those of the 122-mm guns, and the war was drawing to a close, so the vehicle never entered service.