The RCBS #49 Shell Holder was designed to accommodate 45-60 WCF and 40-60 WCF cases, able to adapt any single-stage reloading press for use with those types of cases. With the RCBS #49 Shell Holder, you do not have to buy an entirely new reloading press. RCBS Single Stage shell holders are built from hardened steel and designed to properly align the case with the reloading die in single-stage and turret presses. They're sized to fit specific case heads and capture 0.125 inch of the case head for proper SAAMI headspacing.