Comparing: Rheinmetall Skorpion vs. ISU-130

Development of the second series of self-propelled guns on the basis of the Panther tank was started by the Rheinmetall company in January 1943. The design plans for the 12,8 cm Skorpion were completed on April 2, 1943. Existed only in blueprints.

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.