RCBS Full-Length Die Sets are precision-machined from our proprietary die steel to exacting tolerances, ensuring the best possible performance for hand-loaders. Each set includes two critical components: the Full-Length Sizing Die and the Bullet Seating Die. Designed specifically for reloading bottleneck cases, the set features a Full-Length Sizer Die with an Expander-Decapping Unit and a Seater Die with a Bullet Seater Plug. The Full-Length Sizer Die ensures your case meets SAAMI minimum cartridge dimensions, sizing the case, de-priming it and expanding the neck to properly accept the bullet. The die also incorporates vents to prevent case damage caused by trapped air or excessive lubricant. Additionally, the die maintains precise headspace tolerances to avoid altering the case body length during sizing. The included Seater Die features a built-in roll crimper, securely seating the bullet while crimping it in place for optimal reliability.