My M-I-L found a round in some box in the house. The headstamp reads REM-UMC 32-7.65m/m. If I had to guess I would say it is 32acp but I am not sure as it has something of a semi-rim. She has somewhere an old Iver Johnson in .32s&w so it would make sense if it were that caliber. But I am just not sure.