The Heckler & Koch G41 is a German 5.56×45mm NATO assault rifle introduced in 1981 and produced in limited quantities by Heckler & Koch. It was designed to replace the 7.62×51mm NATO chambered Heckler & Koch G3 and the G3 based .223 Remington/5.56×45mm and later 5.56×45mm NATO chambered Heckler & Koch HK33 service rifles providing a more modern weapon compatible with then recently introduced NATO standards. It can use both the then new STANAG 4172 compliant 5.56×45mm NATO SS109, SS110, and SS111 ammunition and older .223 Remington/5.56×45mm M193 ammunition and was the last Heckler & Koch service rifle designed around the roller-delayed blowback mechanism. Commercially the G41 was not as successful as the preceding Heckler & Koch service rifle designs with a similar operating mechanism. It was rejected by various military trial programmes and it never won a major military production contract. Assembly of the G41 has been discontinued by Heckler & Koch; however, production rights to the rifle were acquired by the Italian arms manufacturer Luigi Franchi. Design details Operating mechanism The G41's engineering origins lay in the 7.92×33mm Kurz StG 45(M) assault rifle, and later the commercially successful 7.62×51mm NATO G3 battle rifle and its 5.56×45mm NATO G33 derivative. It is a selective fire automatic weapon that employs a roller-delayed blowback system of operation relying on geometrical transmission ratio relationships between parts. The two-piece bolt mechanism consists of a bolt head that contains two cylindrical locking rollers and a wedge-shaped locking piece, attached to a heavy bolt head carrier. Based on the geometric relationship arising from the angles of the roller contact surfaces of the wedge-shaped locking piece locking piece and the barrel extension recesses, the rearward motion of the bolt head is delayed by a predetermined ratio. Thus during the same period of time, the bolt head carrier moves significantly faster than the bolt head by the predetermined ratio. This ratio is continued until the locking rollers have been withdrawn from the barrel extension recesses. After the rollers retract entirely behind the bolt head, the locking recesses of the barrel extension are cleared, and all parts continue moving rearward together, opening the breech and actuating the extraction and feeding cycles. The chamber is opened under high pressure, thus the chamber received a series of flutes in order to increase extraction reliability and prevent sticking of the spent casing to the chamber walls. Like the G3 and G33