HK MR556, 5.56mm Semi-Auto Rifle 16.5" Barrel, 1- 30rd magazine
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HK MR556, 5.56mm Semi-Auto Rifle 16.5" Barrel, 1- 30rd magazine

(5 reviews) Write a Review
$3,399.00 $2,851.59
(You save $547.41)
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Ships in 2 to 3 business days
Manufacturer Number:
5.56 x 45mm NATO
223 Remington
HK MR556
Unit of Measure:

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MR556 Match Rifle 5.56mm 16.5 Inch Barrel Black Finish 6-Position Buttstock 30 Round
Features HK-proprietary gas piston system. Does not introduce propellant gases and carbon fouling back into the rifles interior. Rotating bolt system. Cold hammer forged barrel. 6 lands and grooves. 1 in 7 inches right hand twist. Six position adjustable buttstock - 96mm of travel.
A direct descendent of the HK416, the MR556A1 is a semi-automatic rifle developed by Heckler & Koch as a premium level commercial/civilian firearm with match rifle capability. Like the HK416, the MR556A1 is a major product improvement over conventional AR-type carbines and rifles.

The MR556A1 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 MR556A1 is manufactured in the USA using American and German made components.

The MR556A1 also has a Picantinny rail machined into the top of its upper receiver for mounting optics and mechanical sights. Unlike earlier prototypes, major subassemblies, including the MR556A1 upper receiver/barrel assembly, are fully interchangeable with other high quality AR-style firearms. MR556A1 upper receiver kits can be used to retrofit competing legacy AR systems.

Like the famous HK416, the MR556A1 uses a German-made barrel produced by Heckler & Koch’s famous cold hammer forging process. The highest quality steel is used in this unique manufacturing process producing a barrel that provides superior accuracy and long service life.

But unlike the HK416, the MR556A1 does not use a chrome-lined barrel. Chrome-lining can sometimes mask bore imperfections and negatively affect accuracy. For the new series of Heckler & Koch semi-automatic MR rifles, HK designers and engineers believe best accuracy comes with an unlined bore.

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.

A precise enhanced two-stage trigger adds significantly to the accuracy of the MR5556A1 and an extended latch charging handle makes operating the rifle with a telescopic sight easier. The retractable buttstock 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.

Designed to function with a wide variety of high quality 5.56 x 45 mm ammunition, the MR556A1 uses a C.I.P. dimensioned chamber (a chamber with dimensions specified by the Commission Internationale Permanente).The MR556A1 also functions reliably with most quality Caliber .223 Remington ammunition.

The MR556A1 is being produced with the same commitment to quality as 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 designs innovations of the USA and Germany into one new product.
  • Category : Tactical Rifles
  • Action : Semi-Automatic
  • Caliber : 223 Remington/5.56 NATO
  • Barrel Length : 16.5"
  • Capacity : 30+1
  • Trigger : Two Stage
  • Safety : Lever
  • OAL : 33.9"-37.68"
  • Weight : 8.6 lbs
  • Stock Description : Adjustable Black
  • Metal Finish : Black

5 Reviews

  • Worth it

    Posted by Sean on Feb 8th 2016

    I know HK makes great products, but I'm by no means a fanboy; the only other HK I own is a VP9. I thought the MR556 was an equivalent platform to other, less proprietary-minded company's take on the AR....that was until I shot it. After putting a few thousand rounds down range I feel comfortable saying this is the best market AR15 I have ever used. It is worth the price of admission.

  • Correct- best there is

    Posted by Packer on Jun 14th 2015

    I had to scrape up change to afford this rifle - but you're right- it is the best and worth the price of admission. Thanks Impact

  • Best AR on the market

    Posted by SKS is crap on Jun 13th 2015

    Ignore the clown comparing this superior weapon to a heap of crap like an SKS. The two systems are "the same" in the way that a small block chevy v8 is the same as a small block ford: they are both engines with 8 cylinders and pushrods. The MR556 might not be a 416 but it's as close as it gets. Is it pricey? Of course, but so are POF, LWRC and the like, but this HK is the semi-auto version of the one issued to operators. If you want a toy, get a bushmaster, if you want a high quality, durable, reliable, and accurate weapon, made by the best firearms manufacturer on the planet, this is the best AR for the money and the best in the high end bracket.

  • Best feeling AR on the market

    Posted by Engineer on Aug 24th 2013

    Bought this gun last year as somewhat of an impulse purchase. Read about it during development and knew HK was a great brand, but mostly purchased this because it was pretty rare. I have several different ARs and have shot many more, but this gun is the most solid, crisp shooting AR I have experienced. You have to shoot it to believe the feel. It is completely solid, and has a beautiful trigger.

    I am a die-hard LMT and KAC fan, but I do feel this gun is more solid than either. Never gets dirty, never had a malfunction. It is heavy and does not have many gimmicks, but I think this would be a great gun to have if I ever deployed again.

    Also, the magazines from HK are the best made AR mags available. They are heavy, but solid and very reliable. Buy one and see.

  • The best civilian AR style rifle on the market...

    Posted by CDJ on Jan 23rd 2013

    After long debate I broke down and purchased an Hk MR556A1. The price was a hold up for me, but after shooting one, I knew, " it must be mine". This is truly the best built AR type rifle I have ever handled. It is a sub MOA gun, if the operator can do their part. After buying it and comparing it to LWRC or Adams piston AR's the only thing they have in common is the look. I have never shot an AR that stays cleaner or requires less lubrication to keep it running. Even Larry Vickers says this is the Rifle that All other piston AR's will ever be compared to.

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