Lee collet dies can be easily adapted to another case. They are not case diameter specific. Use a shim (washer) between the shell holder and the die for a case that is longer than the case the die was designed for. I make person bushings. Lay your Imp Zipper case along side a 22-250 case and compare shoulder neck junctions. If the Zipper case is longer figure how much of a shim you need and use the collet die. Betting the 22-250 seater would work also. Dale
