HK MR762 A4 13" 7.62x51mm Upper Receiver Kit 5/8×24 51001919

HK MR762 A4 Upper Receiver Kit

The HK MR762 A4 Upper Receiver Kit is a factory-assembled component from Heckler & Koch, designed to upgrade compatible AR-style platforms to their proprietary short-stroke piston system. Chambered in 7.62x51mm, it features a 13-inch cold-hammer forged barrel with 5/8×24 threading, providing enhanced reliability by keeping hot gases and carbon out of the receiver. This kit includes essential parts for seamless integration, offering improved performance over direct-impingement systems.

Key elements include the complete upper receiver with forward assist, an extended convertible charging handle, and the HK Free Floating Rail System handguard for accessory mounting. The adjustable gas block allows fine-tuning for various loads, while the tungsten-filled proprietary buffer and action spring ensure smooth cycling. Its closed piston design minimizes malfunctions and maintenance, drawing from the proven HK417 technology used in military applications.

This upper kit is ideal for shooters seeking to enhance MR762 lowers with superior durability and precision, suitable for tactical training, long-range shooting, or building custom rifles. Its non-firearm classification simplifies purchase without an FFL, making it accessible for enthusiasts aiming to achieve elite-level reliability in demanding environments.

Specifications