HK MR556 A4 | 5.56 NATO | 16.5in TB | 10rd | 81000828

The Heckler & Koch MR556 A4 is a commercial variant of the HK416 platform offering a short-stroke gas piston system designed to reduce fouling in the action and lower maintenance compared with direct-impingement designs. This model includes ambidextrous controls, an M-LOK handguard, and a threaded 16.5-inch barrel finished for service use. It ships with a 10-round detachable magazine and a 6-position synthetic stock for adjustable length of pull.

For optics, a compact low-power variable optic such as a 1-6x or 1-8x scope (for example, a Vortex Strike Eagle 1-6x) pairs well with the MR556 A4 for target work and practical shooting while staying under $1000.

Common applications include range training and competition/practical rifle use where a low-maintenance gas system and modular platform are priorities.

Product Specifications

• The caliber is listed as 5.56 NATO (.223 Rem).
• The barrel measures 16.5 inches and is described as threaded with a 1/2×28 pattern.
• The magazine capacity is 10 rounds using the included detachable magazine.
• The action is specified as semi-automatic.
• The model is identified as the MR556 A4.
• The receiver is described as a fully ambidextrous lower.
• The handguard uses an M-LOK interface and includes ambidextrous QD cups.
• The operating system is a short-stroke gas piston.
• The stock is a 6-position synthetic configuration.
• The rifle includes an ambidextrous safety lever and ambidextrous magazine/bolt release controls.
• The rifle is described as suppressor ready (adjustable gas regulator noted).
• A Picatinny rail is provided for optics mounting.
• One magazine is included: 1 x 10 rd.
• The rate of twist is 1:7.
• The UPC is 642230269415.

The MR556 A4 emphasizes durability and low-maintenance operation through its short-stroke piston system and ambidextrous controls. Its modular furniture and threaded barrel make it adaptable for a range of civilian shooting applications where reliability and ease of upkeep matter.