The Heckler & Koch MR762A1, chambered in 7.62x51mm, is the US civilian version of the HK 417 model. The MR762 was introduced at the 2009 SHOT Show and later replaced by the improved MR762A1 version. The famous AR platform, and the HK416 and 417 rifles, once created to meet a tactical requirement for the American armed services, served as a direct inspiration for the design of the HK MR762. But the HK MR762's core parts and configuration concepts are unique to Heckler & Koch. The operating system is what distinguishes the MR762A1 from other AR variants. While the most of rifles in the AR family employ a direct impingement gas system, the MR uses a short-stroke gas piston. Since the gases vent in the forearm of the rifle instead of the receiver as in a standard direct impingement AR, the major advantage of a gas piston operating system is the cleanliness of the weapon. A few of the AR platform's operational standards include a free-floating front end and barrel, an adjustable buttstock, a pistol grip, and iron sights. The barrel is cold hammer forged, resulting in higher muzzle velocities, a better gas seal, an extended service life, and superior accuracy with a variety of ammunition.