H&K MR556 A4 5.56 NATO 16.5in 10rd Black

About this product

The Heckler & Koch MR556 A4 is the commercial iteration of the HK416-family modern sporting rifle, chambered for .223 Rem/5.56 NATO and built around a short-stroke gas piston system and an adjustable gas regulator. The rifle features a 16.5 in threaded barrel, a slim M-LOK handguard with ambidextrous QD cups, and fully ambidextrous controls for straightforward operation from either shoulder. A 6-position synthetic stock and a single included 10-round magazine complete a configuration aimed at reliable, low-maintenance performance in range and sport shooting contexts.

Key Specifications

• Chambering: .223 Rem/5.56 NATO.
• Barrel measures 16.5 inches and is threaded.
• Magazine capacity is 10 rounds.
• Action type is Semi-automatic.
• Operating system: Short-stroke gas piston.
• Rate of twist: 1:7″.
• NFA thread pattern: 1/2×28.
• Stock: 6-position synthetic.
• Handguard: M-LOK with ambidextrous QD cups.
• Controls: Fully ambidextrous safety, mag and bolt release.

The MR556 A4 combines the low-maintenance advantages of a piston-driven system with the ergonomics and accessory-ready layout modern shooters expect. With a threaded 16.5 in barrel, ambidextrous controls, and an adjustable gas regulator for suppressed or unsuppressed use, it is built for reliable operation and straightforward adaptability at the range or in competitive settings. The rifle’s M-LOK handguard and Picatinny rail provide a flexible platform for optics and accessories while the collapsible stock allows for personalized fit and handling.