50 Roubles Tank Destroyer ISU-130

The ISU-130 was an experimental Soviet self-propelled gun developed in 1944, mounting a 130mm S-26 naval gun on the ISU-152 hull. It never entered serial production — only two prototypes were completed, and the project was dropped in favor of the already-proven ISU-122S. That the Soviet mint chose to commemorate a vehicle that saw no combat and no production run, over dozens of historically significant wartime machines, makes this a genuinely curious editorial decision.