Heckler & Koch MR556A1 5.56 NATO Semi-Auto Rifle, 16.5 in CHF Heavy Barrel, HK M-LOK Handguard, E1 Stock, Matte Black
This later-production MR556A1 combines HK's short-stroke gas piston system with a 16.5-inch cold hammer forged heavy barrel and the updated HK free-float M-LOK handguard featuring integral QD cups and a numbered T-mark top rail. It includes the HK E1 collapsible stock, HK-marked bolt carrier, and a matte black finish. The rifle is in excellent condition and comes with a 30-round magazine, the original case, an HK-branded soft case, and the HK MR556 operator's manual.
Condition
Overall Condition: Excellent condition, showing only faint signs of any prior use or handling.
Bore Overall Condition: Excellent - Clean, mirror finish, no signs of wear.
Bore Rifling: Excellent Rifling - Sharp lands and grooves.
Specific Condition Notes: This example shows little sign of prior use and presents in excellent condition.
What’s Included
- HK-branded soft rifle case with MOLLE webbing and exterior zip pocket
- Original case
- HK MR556 operator's manual
- 1x 30-round metal STANAG-pattern magazine
The MR556A1 uses a semi-automatic, short-stroke gas piston operating system, paired with an HK-marked bolt carrier and AR-15 platform layout. Controls include a manual safety selector with HK pictograms for Safe/Semi, along with a forward assist and case deflector.
The 16.5-inch steel barrel is cold hammer forged, heavy profile, and non-chrome-lined, with a 1:7 RH twist for stabilizing a broad range of 5.56mm NATO projectiles. It is threaded and fitted with a flash hider.
The HK free-float aluminum M-LOK handguard provides modern accessory mounting, while the full-length Picatinny top rail is numbered (T-marked) and includes integral QD sling cups. No iron sights are installed.
Furniture includes the HK E1 collapsible stock and a Magpul pistol grip. Receivers are aluminum alloy in a matte black finish. Markings include Heckler & Koch Inc., Columbus, GA.
This rifle uses a detachable box magazine system with a listed capacity of 30+1 and includes one 30-round magazine.