The HK MR556A1 is the civilian counterpart of the world-renowned HK416, a rifle trusted by elite military and law enforcement units across the globe. This rifle embodies battlefield-proven reliability, precision, and durability, setting it apart in the AR-15 platform category.

At the heart of the MR556A1 is HK’s proprietary short-stroke gas piston system, which eliminates the need for direct-gas-impingement. This closed system keeps exhaust gases out of the receiver, ensuring the rifle runs cooler, cleaner, and more reliably—even under adverse conditions like dust, sand, and mud.

The MR556A1 features a cold hammer-forged barrel crafted from cannon-grade steel with a 1:7" twist rate and a taper-bore design that enhances both accuracy and muzzle velocity. This advanced manufacturing process delivers a barrel with unmatched durability and service life.

With its precise engineering and robust build quality, the HK MR556A1 stands as one of the most reliable and accurate rifles on the market.

Features:

• Proprietary HK short-stroke gas piston system for cleaner and more reliable operation
• Cold hammer-forged barrel made from cannon-grade steel
• 1:7” twist rate with taper-bore design for improved accuracy and velocity
• Fully ambidextrous controls for ease of use
• Includes original HK case and one 30-round magazine

Specifications:

• Caliber: 5.56x45mm NATO
• Action: Semi-Automatic
• Barrel Length: 16.5 inches
• Barrel Type: Cold Hammer-Forged, Taper Bore
• Twist Rate: 1:7"
• Weight: Approx. 8.6 lbs (unloaded)
• Overall Length: 33.9"–37.7" (adjustable stock)
• Stock: Adjustable
• Sights: Optics Ready (no included sights)
• Safety: Ambidextrous Selector
• UPC: 642230262553 | MPN: 81000579