The RCBS 1-1/4"-12 to 1"-14 Press Adapter Bushing allows the use of 1-inch dies, a size of die body found in RCBS's Safari Dies lineup for cartridges like .500 Jeffrey or .505 Gibbs. Note: All RCBS bushings, in presses that include one, are sized at 1-1/4"-12 to 7/8-14.