Comparing: Rhm.-Borsig Waffenträger vs. ISU-130

Developed by the Rheinmetall-Borsig company and designed as a special artillery carrier. The vehicle was designed to carry an artillery system as well as to fire from the chassis. The vehicle utilized the suspension of the Hetzer tank destroyer. Development continued from the end of 1942 through the middle of 1944. However, the project was discontinued in favor of the Ardelt project because of a complicated design, high cost, and excessive weight.

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.