Features: B5 Stock, BCM KAG foregrip, Magpul Pistol Grip, Ambi 60 Degree Safety Selector AR-15 compatibility: It uses the familiar AR-15 pattern, so controls and general configuration are widely understood. .223 Rem / 5.56 NATO: A very common rifle-cartridge family, giving the platform broad ammunition availability. 16-inch barrel: A common general-purpose configuration. Modularity: AR-pattern rifles can accommodate a wide range of configurations and accessories.