RCBS is known for making high-quality reloading equipment. Their shellholders are no different, they are made from high quality steel and will fit virtually any single stage reloading press. Fits:50 BMGNote:Works for both 1-1/2"-12 Threaded Die and 1-3/8"-12 Threaded Die Please note that this shellholder is threaded for use with the Ammomaster Press (and other presses that accept 7/8"-14 threaded shellholders) only.