A German assault rifle that was manufactured by Heckler & Koch. Despite its visual similarity to the M4 carbine, the mechanism of this assault rifle is, in fact, closer to that of the German H&K G36, and not to that of American AR-type rifles. Originally, this new weapon was intended as a replacement module for installation on the lower part of the receiver of the M4 or M16 carbines. However, it later became a complete assault rifle in and of itself.