Sierra Outdoor Master cartridges utilize innovative components and production processes that deliver an economical cartridge suitable for all purposes. Packed with hard-hitting terminal performance. Designed for magazine length and reliable feeding in an AR platform. Cartridges are loaded with brass casings, making reloading with conventional equipment easy and economical. *Note This ammo uses mil-grade primers. Best for use in AR-15s. Primer pockets must be reamed or swaged in order to reload. Specifications: 223 Rem 55 gr Hollow Point Boat-Tail (HPBT) 20 Per Box/10 Cs