The MSR Precision Die System in 450 Bushmaster is a 4-die rifle reloading set engineered specifically for MSR ammunition, intended for anyone reloading for a modern sporting rifle. The set includes a Small Base Size die for smooth chambering and a separate Taper Crimp die for a tight bullet grip. An Ammo Checker cartridge Go gauge is included with each set. The dies come packed in a sturdy, clear cover storage case. Safety note Proper die setup and adjustment are critical for producing safe ammunition. Follow published load data and standard reloading safety practices.