Heckler & Koch MR556 A4 5.56 Nato Rifle 16.5″ Barrel

Heckler & Koch MR556 A4 5.56 Nato Rifle 16.5″ Barrel

When precision matters and reliability is non-negotiable, the Heckler & Koch MR556 A4 delivers. Engineered as the commercial evolution of the legendary HK416, this rifle is built for shooters who demand uncompromising quality in every shot. Whether you’re on the range, in the field, or defending what matters most, the MR556 A4 offers unmatched durability, accuracy, and control.

Featuring a cold-hammer-forged match-grade barrel, short-stroke gas piston system, and fully ambidextrous controls, this rifle is optimized for suppressed and unsuppressed operation. Its M-LOK free float handguard, HK USA enhanced grip, and six-position adjustable stock ensure ergonomic handling and modular flexibility. With rugged components like the HK416 A5 upper receiver, elongated steel castle nut, and QD end plate, the MR556 A4 is built to perform under pressure—and built to last.

Cold-Hammer-Forged BarrelMatch-grade 16.5″ barrel delivers exceptional accuracy and long-term durability.

Short-Stroke Gas Piston SystemCleaner operation with reduced fouling for lower maintenance and longer service life.

Suppressor-Ready ThreadsConcentric 1/2×28 threading ensures compatibility with most suppressors and muzzle devices.

Fully Ambidextrous ControlsSafety, bolt release, and magazine release for seamless operation by left- or right-handed users.

Adjustable Gas BlockTwo-position regulator allows tuning for suppressed or unsuppressed shooting.

M-LOK Free Float HandguardSlim profile with integral ambi QD cups for lightweight modular accessory mounting.

HK416 A5 Upper ReceiverContinuous Picatinny rail interface for optics and accessories.

Enhanced ErgonomicsHK USA grip and six-position stock provide comfort and control in any shooting stance.

Reliable FeedingUpdated angled magazine well ensures smooth reloads under stress.

Battle-Proven ComponentsIncludes HK416 elongated steel castle nut and ambi QD end plate for rugged durability.

Specifications

• Caliber: 5.56 NATO / .223 Remington
• Action: Semi-Automatic, Short-Stroke Gas Piston
• Barrel Length: 16.5″ Cold-Hammer-Forged, Match-Grade
• Thread Pattern: 1/2×28 Suppressor-Ready
• Finish: Black Anodized
• Handguard: M-LOK Free Float with Integral Ambi QD Cups
• Receiver: HK416 A5 Upper with Continuous Picatinny Rail
• Stock: HK416 Six-Position Adjustable
• Grip: HK USA Enhanced Grip
• Magazine Capacity: 30 Rounds
• Magazine Included: 1
• Safety Selector: Ambidextrous with 45-Degree Throw
• Gas Block: HK416 Two-Position Adjustable
• Castle Nut: HK416 Elongated Steel
• End Plate: Ambidextrous QD
• Magazine Well: Updated Angled Design for Reliable Feeding