RCBS Full-Length Die Sets are precision-machined from proprietary die steel to the highest tolerances, ensuring exceptional quality and performance for hand-loaders. Each set includes a Full-Length Sizer Die and a Bullet Seating Die, specifically designed for reloading bottleneck cases. The Full-Length Sizer Die features an Expander-Decapping Unit and is engineered to size the case to SAAMI minimum cartridge dimensions, de-prime and expand the neck for proper bullet seating. Vent holes are included to prevent damage from trapped air and excessive lubricant. Headspace is precisely controlled to avoid altering the case body length during full-length sizing. The Seater Die incorporates a built-in roll crimper that securely crimps the bullet while seating it, ensuring consistent, reliable ammunition with every load.