For those want uncompromised performance and the durability to last a lifetime. A U.S. made version of the famous HK G8 50 round drum for your HK91 and G3 style rifle. The X-91 is a .308 caliber drum that is easy to load/unload and boasts a full 50 round capacity. All internal & operating assemblies are made of steel, aluminum, with a high impact, glass filled nylon follower system. Each drum comes with an easy to follow owners manual & loading instruction manual. All drums are backed by a hassle free lifetime warranty. HK Parts has had extensive testing done with the X-91 50 round drum magazine with zero issues! This is one of the best drum design we have encountered to date.