This cartridge has been somewhat of a mystery. It is listed in the ECRA Database as 07 036 CBC 010   7 x 35,5 R Utendoerffer Unknown

CASE LENGTH:  = 35.35mm
CASE MOUTH:    = 6.85mm
NECK:                  = 7.50mm
BASE:                   = 7.50mm
RIM:                     = 8.83mm