RCBS Full-Length Die Sets are precision-machined from proprietary die steel, crafted to exacting tolerances and finished through a meticulous process to deliver the best reloading experience for hand-loaders. Each set includes a Full-Length Sizing Die and Bullet Seating Die, designed for reloading bottleneck cases. The Full-Length Sizer Die, featuring an Expander-Decapping Unit, brings the case to SAAMI minimum cartridge dimensions, sizes the case exterior, de-primes and expands the neck to properly seat the bullet. Vents in the die help prevent case damage from trapped air and excessive lubricant. With precise headspace tolerances, the Full-Length Sizer Die ensures that the case body length remains unchanged during the sizing process. The Seater Die, equipped with a Bullet Seater Plug, also includes a built-in roll crimper to securely hold the bullet as it's seated.