Heckler & Koch H&K MR 556 A1 5.56/.223 16.5″ HK416 E1 AR-15 Rifle MLOK

SOLD FOR: $2425

WOA#: WY221229GC001

Our Assessment: The MR556A1 is a semi-automatic rifle manufactured by Heckler & Koch, which is a company known for producing high-quality firearms used by military and law enforcement worldwide. This rifle is designed to be a premium level commercial/civilian firearm with match rifle capability.

One of the key features of the MR556A1 is its use of the HK proprietary gas piston operating system, which is a major improvement over conventional AR-type carbines and rifles. Unlike direct impingement gas systems that are common in AR15/M16/M4-style firearms, the gas piston system virtually eliminates malfunctions due to hot carbon fouling and waste gases that can enter the receiver area. This feature is critical to the success of the HK416 rifles, which are used by leading military and law enforcement customers.

The MR556A1 is manufactured in the USA using American and German made components. It uses many of the same assemblies and accessories originally developed for the HK416, making it a reliable and accurate rifle. The rifle is designed to function with a wide variety of high-quality 5.56 x 45 mm ammunition and uses a C.I.P. dimensioned chamber, which is a chamber with dimensions specified by the Commission Internationale Permanente. It also functions reliably with most quality Caliber .223 Remington ammunition.

The MR556A1 features a free-floating barrel/handguard relationship, which ensures maximum accuracy. The barrel does not touch the handguard, allowing the barrel to vibrate freely and increasing its accuracy. The rifle can be used with either the HK Modular Rail System (MRS) or the Free Floating Rail System (FFRS). The MRS handguard has many of the features found on the FFRS but with a more ergonomic design, while the FFRS handguard has four MIL-STD-1913 Picatinny rails, allowing all current accessories, sights, lights, and aimers used on M4/M16-type arms to be fitted to the MR Series. Both HK rail system handguards can be installed and removed with simple tools and return to zero when reinstalled. The MR556A1 also has a Picatinny rail machined into the top of its upper receiver for mounting optics and mechanical sights.

The MR556A1 uses a German-made barrel produced by Heckler & Koch’s famous cold hammer forging process, which is a unique manufacturing process that uses the highest quality steel to produce a barrel that provides superior accuracy and long service life. However, unlike the HK416, the MR556A1 does not use a chrome-lined barrel. The unchromed barrel has an internal profile of 6 lands and grooves with a 1 in 7 inch (178 mm) twist. It is also moderately “swagged” with a slightly smaller internal diameter at the muzzle end than the chamber end. This feature has a positive effect on bullet accuracy and velocity. The thick, heavy contour 16.5-inch MR556A1 barrel also contributes to its excellent accuracy.

Other features of the MR556A1 include a precise enhanced two-stage trigger that adds significantly to the accuracy of the rifle, an extended latch charging handle that makes operating the rifle with a telescopic sight easier, and a retractable buttstock that can be locked into a solid, non-moving position by tightening an Allen screw in the bottom of the stock. Special target rifle takedown pins ensure the upper and lower receivers are firmly mated for accurate performance.

Overall, the MR556A1 is designed with a commitment to quality that is consistent with other German-made HK firearms. By using joint U.S./German manufacturing, Heckler & Koch leverages the relative strengths of two continents to make the preeminent AR-type firearm, combining the design innovations of the USA and Germany into one new product

Make: Heckler & Koch HK

Model:  MR556A1

Serial Number: 241-403647

Year of Manufacture: Modern

Caliber: 5.56, .223

Action Type: Semi-Automatic, Proprietary Gas Piston

Markings: The left side of the magazine well is marked “HK MR 556 A1 5.56mm X 45” and “241-403647” behind the bolt catch with bullet diagrams for the ambidextrous safety selector.  The right side is marked with “Heckler & Koch Inc. Columbus GA”. The buffer is marked with a red dot in the center and “HK” marked above.  The BCG is marked, “HK MR”.  The right side of the handguard is marked with an M-LOK Logo.

Barrel Length: 16.5.   17.5 with birdcage flash hider.

Stock Configuration & Condition:  The stock is a HK416 E1 Buttstock featuring Ergonomic cheek welds for improved firing position, Two waterproof compartments for storing up to 6 batteries, twist off padded rubber buttplate, multiple sling attachment points, and multi position adjustment.  The handguard is a MLOK rail with ambi QD mounts.  There is no visible wear along the surface except for a few loose storage marks. The pistol grip is an ergonomic textured polymer grip with a water tight storage compartment.  The stock rates in about Excellent overall condition.

Magazine Quantity & Condition: Currently has a 10rd Compmag installed.

Type of Finish:  Anodized Black

Finish Originality: Original

Bore Condition: The bore is bright and the rifling is sharp.  There is no erosion in the bore.

Overall Condition:  This rifle retains about 99% of its metal finish. The balance of the finish shows minimal wear.  This is a CA compliant rifle that appears to have been used very little if at all (a perk of guns coming from CA).  The screw heads are sharp and pins are unmarred. The markings are clear. Overall, this rifle rates in about Excellent condition.

Mechanics:  The magazine is fixed to the receiver and just needs some slight modification to the mag button to release the magazine.  The action functions correctly. This firearm has ambidextrous safety.  We did not fire this rifle. As with all used firearms, a thorough cleaning may be necessary to meet your maintenance requirements.

Box, Paperwork & Accessories: Total of one magazine.

Heckler & Koch H&K MR 556 A1 5.56/.223 16.5" HK416 E1 AR-15 Rifle MLOK
Heckler & Koch H&K MR 556 A1 5.56/.223 16.5″ HK416 E1 AR-15 Rifle MLOK