Heckler and Koch 81000586: Like its 5.56mm counterpart, the MR762A1 is a direct descendent of the HK416/417 series, only in a semi-automatic rifle configuration developed for civilian users. 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. 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 and more reliably. And 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 worlds elite military and law-enforcement customers have absolute trust in their HKs.