H&K MR556 A4 5.56 NATO 16.5in 30rd Black

About this product

The Heckler & Koch MR556 A4 is the commercial variant of the HK416 platform configured as a modern sporting rifle. It uses a short-stroke gas piston system and an adjustable gas regulator to support suppressed or unsuppressed operation while reducing carbon fouling in the action. The rifle ships with a 30-round detachable magazine, a 16.5-inch threaded barrel and M-LOK compatible handguard for accessory mounting. Fully ambidextrous controls and a multi-position stock provide ergonomic operation for a wide range of users.

Key Specifications

• Caliber is .223 REM / 5.56 NATO.
• The barrel measures 16.5 in and is threaded.
• Magazine capacity is 30 rounds.
• The action is Semi-Auto.
• The rifle features a threaded barrel for muzzle device compatibility.
• The rifling rate of twist is 1:7.
• The overall length is 36.5 in.
• The stock is a 6-position polymer design.
• The lower receiver is fully ambidextrous.
• The muzzle thread pattern is 1/2×28.

Built as a commercial HK416-style platform, the MR556 A4 blends piston-driven reliability with accessory-ready ergonomics and suppressor-capable features. Its combination of ambidextrous controls, M-LOK modularity and a multi-position stock make it well suited for range use, training, and professional applications where durability and low-maintenance operation are priorities.