Originally manufactured in West Germany in 1981, this rifle was subsequently converted to a fully automatic machine gun in HK53 configuration by Fleming Firearms, which included permanently modifying the receiver from the semi-auto only "shelf" configuration to the full auto "pin" configuration. Post front and four-position drum rear sight, with a long four-pronged flash hider on the "ICU" marked barrel", Fleming markings added to the left side near the claw mounts, "HK53" and the "IB" date code on the left side of the magazine well and HK Inc. address on the right side. As noted, the "shelf" has been trimmed down, and a functional paddle release for the magazine installed, with a triangular forearm, textured pistol grip with ambidextrous "full/3-round/semi/safe" pictographic markings, and a two position telescoping buttstock. The trigger pack is fitted with an ambidextrous selector, and configured to match the external markings. The bolt and bolt carrier are both dated "IB", with the latter altered to trip the auto sear.