RCBS has been making some of the best reloading equipment for over 60 years. Their 2-Die Sets are known in many reloading circles for their high-quality. Each 2-Die set includes a full length sizer die has an expander-decapping unit to remove the spent primer while expanding the case mouth. Vent holes prevent case damage caused by trapped air or excessive lubricant. The seater die includes a Bullet seater plug and built-in roll or taper crimp as appropriate for the particular cartridge. Type: 2 Die set fits: 257 Weatherby Magnum note: uses shellholder #4 (sold separately).