Heckler & Koch MR556 A4 5.56 NATO 16.5" Midnight Bronze Cerakote 30+1 81001528

Heckler & Koch MR556 A4

The Heckler & Koch MR556 A4 is a semi-automatic rifle chambered in 5.56 NATO with a 16.5-inch barrel finished in Midnight Bronze Cerakote. This model utilizes a short-stroke gas piston operating system that keeps fouling out of the action for consistent reliability. It ships with one 30-round magazine along with a Holosun HS510C optic and Dead Air Xeno muzzle brake as part of the package. The design emphasizes premium construction and ambidextrous controls for versatile handling in various conditions.

Specific features include a free-floating HK-USA Slimline M-LOK handguard that supports accessory mounting while allowing the barrel to float freely. The 2-stage trigger provides a distinct break for improved shot placement, and the adjustable gas regulator supports both suppressed and unsuppressed operation. A black synthetic adjustable stock pairs with the cold hammer-forged barrel featuring a 1 in 7 inch right-hand twist. Overall length measures 36.5 inches and the rifle weighs 7.67 pounds without the magazine, delivering a balanced platform with a Picatinny rail on the upper receiver.

This configuration suits sporting, competition, and defensive applications where reliability and precision matter. The piston system reduces maintenance needs compared to direct-impingement designs while the included optic and muzzle brake ready the rifle for immediate use. Fully ambidextrous controls and the suppressor-ready barrel enhance adaptability for left or right-handed shooters. The Midnight Bronze Cerakote finish adds durability and a distinctive appearance for users seeking a high-end AR-style rifle.

Specifications