A direct descendant of the world-famous HK416, the MR556A1 is the commercial carbine from the same DNA. It offers the battlefield-proven reliability, durability and precision you would expect from a rifle that bears the name Heckler & Koch. The MR556A1 is assembled in the USA using US and German-made components and uses many of the same parts and assemblies developed for the HK416.

Like the HK416, the MR556A1 uses a proprietary HK short-stroke gas piston in place of the direct-gas-impingement system found on lesser AR15-style rifles that propels exhaust gas into the upper receiver to operate the action. In the “closed” HK piston system, exhaust gasses never enter the receiver, which means the HK runs cooler, cleaner and more reliably.

The MR556A1’s barrel is cold hammer forged from the highest quality cannon-grade steel. It has a 1 in 7” twist and a taper-bore configuration, with a slightly smaller diameter at the muzzle for improved accuracy and velocity. And while the material and cold hammer forging process themselves greatly enhance durability, HK’s processes include many additional steps not taken by other manufacturers to produce superior accuracy and service life, ensuring performance well beyond “mil-spec.”

Ships in HK soft case with one 30-round magazine.

The latest update from HK-USA to the commercial variant of the legendary HK416, the MR556 A4 represent an enhanced example of “no compromise” HK performance. Its short-stroke gas piston operating system does not impart hot carbon fouling back into the action, allowing the weapon to run longer, with less maintenance and with less wear on internal components than direct-impingement ARs. Its adjustable gas regulator allows the operator to tune the action specifically for suppressed or unsuppressed operation. Fully ambidextrous controls, lighter weight and a slimmer profile make the new A4 easier to operate, manipulate and employ. For those who demand an AR with unmatched capability and uncompromising reliability and durability, the MR A4s remain the top tier solution.

In 2010, the US Marine Corps adopted the HKM27 as its new Infantry Automatic Rifle (IAR). The rifle is named for the 1st Marine Division, 2nd Battalion, 7thRegiment, that tested the rifles and IAR (infantry automatic rifle) concept for more than a decade. Replacing the M249 for rifle squads, the M27 was once declared, "The most tested weapon in the history of the Marine Corps". The M27 has proven itself again and again, from the test ranges at Twenty nine Palms to the Global War on Terror - and beyond. With its precision, durability, and reliability, the M27 expanded beyond the initial role of IAR. The M27 is fielded today as an IAR, precision rifle, general infantry rifle, and most recently as a short-barreled upper receiver Reconnaissance Weapons Kit (RWK). Now civilians can own a piece of Marine Corps history with a limited - run HKMR27, a civilian - legal tribute to the M27. The MR27 uses the same HK DNA and offers the battlefield - proven reliability, durability, and precision of a worthy homage to such a proven military rifle. Includes HK branded FDE hard case with wheels, Limited Edition Coin, and Ships (1) 30RD FDE magazine.

The latest update from HK-USA to the commercial variant of the legendary HK416, the MR556 A4 represent an enhanced example of “no compromise” HK performance. Its short-stroke gas piston operating system does not impart hot carbon fouling back into the action, allowing the weapon to run longer, with less maintenance and with less wear on internal components than direct-impingement ARs. Its adjustable gas regulator allows the operator to tune the action specifically for suppressed or unsuppressed operation. Fully ambidextrous controls, lighter weight and a slimmer profile make the new A4 easier to operate, manipulate and employ. For those who demand an AR with unmatched capability and uncompromising reliability and durability, the MR A4s remain the top tier solution.

A direct descendent of the HK416, the MR556 is a semi-automatic rifle developed by Heckler & Koch as a premium level commercial/civilian firearm with match rifle capability. Like the HK416, the MR556 is a major product improvement over conventional AR-type carbines and rifles. The Heckler & Koch MR556 uses the HK proprietary gas piston operating system, employing a piston and a solid operating pusher rod in place of the gas tube normally found in AR15/M16/M4-style firearms. This method of operation virtually eliminates malfunctions that are common to direct impingement gas systems since hot carbon fouling and waste gases do not enter the receiver area. This is the same key feature critical to the success of the HK416 rifles used by leading military and law enforcement customers. The MR556 Competition model features input from competitive shooters and is designed for enhanced performance in a competitive or duty environment. Features a 14" Modular keymod rail system, lightweight Magpul CTR stock, muzzle brake, oversized, extended magazine release, extended charging handle, two stage trigger, and cold hammer forged 16.5" barrel.

The latest update from HK-USA to the commercial variant of the legendary HK416, the MR762 A4 represent an enhanced example of “no compromise” HK performance. Its short-stroke gas piston operating system does not impart hot carbon fouling back into the action, allowing the weapon to run longer, with less maintenance and with less wear on internal components than direct-impingement ARs. Its adjustable gas regulator allows the operator to tune the action specifically for suppressed or unsuppressed operation. Fully ambidextrous controls, lighter weight and a slimmer profile make the new A4 easier to operate, manipulate and employ. For those who demand an AR with unmatched capability and uncompromising reliability and durability, the MR A4s remain the top tier solution.

The HK MR762 has been engineered based on the HK417 design, but in a semi-automatic configuration for civiliam use. The MR762 uses the HK Gas Piston System, consisting of a piston and operating rod which reduces wear and carbon fouling. This increases reliability over gas impingement systems. The MR762 comes standard with ambidextrous controls, free floating MLOK handguard, and a two stage trigger.