Product Overview
Details
Designed for standard AR-style rifles, the Heckler & Koch MR556 A4 Complete Upper Receiver Kit is a 5.56 NATO assembly featuring HK’s short-stroke gas piston system. This kit contains an 11-inch cold hammer forged barrel, a complete upper receiver featuring a forward assist, and an extended convertible charging handle. The HK Free Floating Rail System handguard offers a stable mounting platform and reduces barrel deflection. The HK416's operating system is incorporated into this upper, minimizing carbon buildup and enhancing its reliability. This upper kid also includes an MR556 bolt carrier group, a custom buffer system, an adjustable gas block, and a soft case for transport.
Features:
- 5.56 NATO complete upper receiver
- 11" cold hammer forged barrel
- 1:7 rate of twist
- Short-stroke gas piston system minimizes fouling
- HK Free Floating Rail System handguard
- Complete MR556 bolt group included
- Extended convertible charging handle
- HK proprietary tungsten-filled buffer and buffer spring
- Adjustable gas block for suppressed or unsuppressed use
- Includes HK-branded soft case
