Ammo Caliber: .223 Remington - Bullet Weight: 55 Grain - Bullet Type: Full Metal Jacket (FMJ) - Use Type: Range Training - Ammo Casing: Zinc Plated Steel - Rounds Per Box: 20 - This high quality ammo features distinctive highly polished zinc plating on the cartridge case; hence the Silver Bear name. Silver bear offers high quality at reasonable prices. Other manufactures reserve the silver cases for law enforcement safari and specialty ammo. This product uses Berdan priming for long shelf life and sure-fire ignition. Silver Bear is loaded to exacting standards.