Description
The MR556A1 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. The MR556A1 has a cold hammer forged barrel made from cannon-grade steel, producing a barrel that ensures accuracy, even after firing thousands of rounds. Includes four 10rd magazines.