Heckler & Koch MR556 A4 5.56mm NATO 16.5-Inch Semi-Auto Rifle with Short-Stroke Gas Piston
This Heckler & Koch MR556 A4 is a semi-auto 5.56mm NATO rifle from the MR A4 Series, built on the AR-15 platform and using a short-stroke gas piston operating system with an adjustable gas regulator. It features a cold-hammer-forged match barrel with a 1:7 right-hand twist, a free-float M-LOK handguard, and a full-length numbered Picatinny top rail. Markings include "MR 556 A4" and "5.56 mm x 45" on the receiver, HK logo markings, and Heckler & Koch Inc., Columbus, GA import markings.
CONDITION
Overall Condition: Excellent condition, showing only faint signs of any prior use or handling.
Mechanics: The firearm is in excellent condition and function, with little sign of prior use.
Bore Condition: Excellent - Clean, mirror finish, no signs of wear.
Bore Rifling: Excellent Rifling - Sharp lands and grooves.
WHAT'S INCLUDED
- HK-branded soft rifle case
- HK "Operator's Manual - MR A4 Series" (original manual)
- HK Multi Allen Key tool
- 1x 30rd detachable AR-pattern magazine
The MR556 A4 is marked with HK branding throughout, including HK logo markings on the lower and visible on the bolt carrier along with "MR." The selector lever uses pictogram markings in red and white, and the receiver is marked "MR 556 A4" and "5.56 mm x 45."
This rifle uses a short-stroke gas piston action with an adjustable gas regulator. Up front, it has a free-float M-LOK handguard and a full-length numbered Picatinny top rail, with index numbers visible in the 2-34 range.
The barrel is a 16.5-inch cold-hammer-forged match barrel with a 1:7 right-hand twist. The muzzle device is a multi-slot/open-prong style.
Furniture includes a polymer, adjustable telescoping stock and an HK-branded polymer pistol grip. The length of pull is stated as 10.5 inches and 14 inches.