- Short-Stroke Gas Piston Operating System
- Cold Hammer-Forged 7.62x51mm Barrel
- Free-Float M-LOK Handguard
- Adjustable Gas Block, Suppressor-Ready
- Includes HK BCG, Buffer, and Buffer Spring
- Fits Mil-Spec AR-10/SR25-Pattern Lowers
- Color: Matte Black
- Caliber: 7.62x51
- MPN: 51001892
The Heckler & Koch MR762A4 Upper Receiver Kit converts a mil-spec AR-10/SR25-pattern lower into HK's proven short-stroke gas piston operating system in 7.62x51mm NATO. The 16-inch cold hammer-forged barrel delivers excellent accuracy with a 1:10 twist optimized for 7.62 NATO ammunition, and the adjustable gas block accommodates both suppressed and unsuppressed firing. The free-float M-LOK handguard features a full-length Picatinny top rail. Kit includes the HK bolt carrier group, buffer, and buffer spring. Hot carbon fouling is vented away from the action, maintaining the reliability and cleanliness HK piston systems are known for.
