H&K MR556 A4 5.56x45mm 16.5in 10+1 Patriot Brown

The Heckler & Koch MR556 A4 is a semiautomatic AR-pattern rifle chambered in .223 Rem/5.56 NATO designed for dependable range, duty, and precision shooting applications. It employs a short-stroke gas piston operating system that reduces carbon fouling in the action and lowers wear on internal components. An adjustable gas regulator allows tuning for suppressed or unsuppressed operation. Fully ambidextrous controls, a slimmer profile and a six-position synthetic stock provide ergonomic handling across diverse shooters and setups.

Key Specifications

• The caliber is .223 REM/5.56 NATO.
• The action is Semi-Auto.
• The capacity is 10 + 1.
• The barrel measures 16.50″ and is threaded for accessories.
• The barrel description is Threaded.
• The rate of twist is 1:7″.
• The unloaded weight is 7.67 lbs.
• The overall length is 36.50″.
• The stock is a 6 Position black synthetic design.
• The safety/controls are Ambidextrous Safety Lever.

With a piston-driven system, adjustable gas regulator and modern accessory-ready ergonomics, the MR556 A4 is built for shooters who value low-maintenance operation and solid performance on the range or in professional applications. Its combination of a threaded 16.50″ barrel, M-LOK handguard and ambidextrous controls makes it a practical, user-focused option for those prioritizing durability and straightforward functionality.