Wolf Military Classic Centerfire Rifle Ammunition is made up of steel and copper and works best with AR-15s. This ammunition has a full metal jacket and comes with a dry storage box. These bullets are partially copper-coated and partially metal-coated making them easy to reload and allowing for hassle-free shooting. This feature also prevents firearm glitches. Many trials show that even after 400 straight rounds these bullets were still fired without mishaps. Though they are a bit dirty and messy you can clean your weapon right after a shooting spree. The mess is nothing compared to the ammunition's excellent performance.