Theis a German Assault rifle developed by Heckler & Koch in 2004. The HK416 shares lower receiver, magazine, receiver extension, grip, trigger assembly and stock with normal AR-15 rifles, like the M16 and M4 carbine , leading to a level of parts commonality, weapon familiarity and relative low cost. The HK416 uses a short-stroke piston design from the G36 that cycles the bolt carrier, instead of the direct gas impingement system used by the AR-15, which prevents carbon build up inside the bolt carrier to avoid weapon failure and increase reliability and lifespan of the weapon. It is currently in use by many countries around the world including, but not limited to, the United States, Norway, Poland, Singapore, and Turkey.