If your shell holder doesn't securely grip the sell and firmly fit into the press during reloading, you're bound to have headspace and sizing problems. RCBS manufactures their shell holders to the industry's tightest tolerances, using only the finest steel.

Features and Specifications:
Manufacturer Number:99243
Fits:
.223 Winchester Super Short Magnum
.243 Winchester Super Short Magnum
.25 Winchester Super Short Magnum
.270 Winchester Short Magnum
7mm Winchester Short Magnum
.300 Winchester Short Magnum
.325 Winchester Short Magnum