HK MR556 A4 Rifle, 5.56 NATO, 16.5-Inch, Patriot Brown

The HK MR556 A4 in 5.56x45mm NATO (brand part no. 81001204) is Heckler & Koch’s civilian-legal take on its short-stroke gas piston military rifles, built for shooters who want a cleaner-running action with less maintenance. Heckler & Koch finishes the upper in a two-tone Patriot Brown over a black 16.5-inch threaded barrel, and wraps it in an M-LOK handguard that keeps the profile slim for easier handling. A 6-position adjustable black synthetic stock and fully ambidextrous controls make the MR556 A4 comfortable for right- and left-handed shooters alike, and an adjustable gas regulator lets the operator tune the action specifically for suppressed or unsuppressed fire. Among AR rifles, the MR556 A4 suits shooters who want proven HK piston engineering in a lighter, more ambidextrous package.

Key Specifications

• Chambered in .223 Remington/5.56 NATO.
• Rate of twist is 1:7 inches.
• Holds a 10+1 capacity with the included magazine.
• Barrel measures 16.5 inches.
• Barrel is threaded and finished in black for muzzle devices.
• Receiver is finished in two-tone Patriot Brown with a Picatinny rail.
• Handguard is M-LOK compatible for accessory mounting.
• Stock is a 6-position adjustable black synthetic stock.
• Controls are fully ambidextrous, including the safety lever.
• Runs a short-stroke gas piston system with an adjustable gas regulator tunable for suppressed or unsuppressed use.

Frequently Asked Questions

What is the barrel length? 16.5 inches, threaded for muzzle devices.

Is this rifle tunable for suppressor use? Yes, the adjustable gas regulator lets shooters tune the action specifically for suppressed or unsuppressed fire.

Does it have ambidextrous controls? Yes, including a fully ambidextrous safety lever for left- and right-handed shooters.

Buy the HK MR556 A4 Rifle

A slimmer, lighter evolution of HK’s piston-driven rifle line, the MR556 A4 gives shooters tunable performance in a fully ambidextrous package. Order it from our Lubbock, Texas gun shop for fast, insured shipping to your FFL.