A weapon is only as reliable as its magazine. Designed by HK to provide an uncompromising reliable feeding source for existing M16 type systems, the HK High Reliability Magazine has been combat proven by various U.S. Special Operations and foreign military units worldwide. Its superiority has been evidenced throughout extensive testing in arctic, desert, jungle, and maritime environments. It features a well-executed design, select materials, special anti-friction surface finish, advanced spring material, attention to production tolerances, and a heat-treated steel magazine housing and follower. For use in extreme environments HK now offers a special Maritime coating which easily surpasses the US MIL-STD-810 E salt fog test. During this test, the HK High Reliability Magazines were exposed to a 100 hour salt fog and then stored three days at ambient temperature. After this test procedure each magazine was fully loaded with rounds and fired twice with no problems experienced. In U.S. military testing, the HK magazine improved feeding reliability of the system by 30-50% overall.