Dies are the heart of the reloading process, and RCBS is the industry leader for quality dies. Engineered to the highest standards and manufactured to the tightest tolerances, theyre constructed from case-hardened steel, precision-drilled, reamed, polished and hand-inspected twice before leaving the factory. No other manufacturer holds their product to such a high standard. Small Base Sizing Dies size the brass just a little bit smaller than factory spec, to ensure flawless function in AR Type rifles. RCBS dies can be counted on to produce consistent and reliable results for shooters who demand reloads equal to the quality of their firearm. Includes plastic storage box and loading data table. Full-length sizer dies for bottleneck cases have vents to prevent case damage from trapped air and excessive lubricants. Seater dies have a built-in roll or taper crimper. Large, easy-to-adjust hex-lock rings.