Like its 5.56mm counterpart the MR762A1 is a direct semi-automatic descendent of the HK416/417 series. It is assembled in the USA using US and German-made components and uses many of the same parts and assemblies developed for the legendary HK416 and 417. - This latest update to the MR762A1 includes an updated grip and forearm as well as a lighter barrel profile that removes nearly a pound of front-end weight from the rifle. - Like the HK416/417 the MR762A1 uses a proprietary HK short- stroke gas piston in place of the direct-gas-impingement system found on lesser AR15-style rifles that propels exhaust gas into the upper receiver to operate the action. In the closed HK piston system exhaust gasses never enter the receiver which means the HK runs cooler cleaner. That is where that legendary HK reliability comes from. - When adverse conditions like dust sand and mud are introduced the advantage of the HK system becomes even more drastic. That is why so many of the world's military and law-enforcement elite customers trust HK. - The MR556A1's barrel is cold hammer forged from the highest quality cannon-grade steel with a slightly smaller diameter at the muzzle for improved accuracy and velocity. While the material and cold hammer forging process themselves greatly enhance durability HK's processes include many additional steps not taken by other manufacturers to produce superior accuracy and service life ensuring performance well beyond mil-spec. - Caliber: 7.62 x 51 mm NATO - Operating principle: Gas operated short stroke piston - Bolt system: Rotating bolt - Magazine: 10/20 rounds - Mode of fire: Semi-automatic - Length maximum (stock extended): 39.50 in / 1003 mm - Length minimum (stock retracted): 36.00 in / 914 mm - Width: 3.23 in / 82 mm - Height: 8.39 in / 213 mm - Barrel length: 16.5 in /421 mm - Weight Rifle (with empty magazine): 8.84 lb /4 kg - Trigger pull: 4.5 5.6 lb / 20 25N ( two stage trigger) - Barrel profile: 4 lands & grooves right twist 1 in 11.02 in (280 mm) - Sights Optics ready - Adjustable buttstock 6 positions 80 mm of travel