RCBS Small Base Taper Crimp Die Set - AR Series. They feature a Small Base Sizer Die designed for semi-automatic firearms and a Taper Crimp Seater Die. The Small Base Sizer guarantees the cartridge will rechamber in AR-platform weapons. RCBS AR Series Small Base Die Set comes with our 7-degree taper crimp seater die and the sizing die is special in that it sizes the brass smaller than SAAMI specifications. This helps aid greater reliability in semi-automatic rifles like the AR-15 pattern rifle and more. If feeding reliability is a must in your semi-auto - These are the dies for you. Specifications for RCBS AR Series Die Set: Manufacturer: RCBS Caliber: .22 ARC (Advanced Rifle Cartridge) Width: 4.55 in Height: 1.75 in Projectile Caliber: .22 Caliber Country of Origin: USA Included Accessories: 2 Dies in a Set Features of RCBS AR Series Die Set Features a Small Base Size Die to insure feeding in semi-automatic firearms Taper Crimp Seat Die crimps bullets so they will not move during recoil Unique 7-degree crimp angle designed for taper crimps in autoloading rifles Comes in a Black Die Box All RCBS dies are machined to exacting tolerances hardened and finished to the highest standards in the industry Package Contents: RCBS AR Series Die Set RCBS 30207: Small Base Taper Crimp Die Set - AR Series