Heckler & Koch HK416
The Heckler & Koch HK416 is an assault rifle chambered for the 5.56×45mm NATO cartridge, designed and manufactured by the German company Heckler & Koch. Although the design is based on the selective fire AR-15/M16 class of firearm (specifically the Colt M4 carbine family issued to the U.S. military), it uses a proprietary short-stroke gas piston system from the Heckler & Koch G36 family of rifles.