HK MR556A1 Competition 5.56 NATO, 16.5 in Heavy Barrel, Short-Stroke Piston, Extended MRS Rail
The HK MR556A1 Competition stands out with a heavy-profile, cold hammer forged 16.5 in barrel, a short-stroke gas piston system, and HK's extended MRS free-float handguard. This example bears the HK proof/date code "BH" (2017), features ambidextrous controls, and is marked with factory competition rollmarks. It is in excellent condition with a clean, mirror-finish bore.
Built with an unlined, free-floated barrel and a 1:7 twist, this Competition variant is configured for durability and consistent performance. The 14 in HK MRS handguard provides a continuous T-marked Picatinny top rail, integral QD sling cups, and keyhole-style slots, while the helical multi-port compensator caps the barrel. No iron sights are installed from the factory on this configuration.
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: There are minimal signs of prior use. The rifle presents in excellent condition, and the bore is clean and shiny.
What’s Included
- HK soft case
- Original case
- Original manual
- 1x 30-round MFT polymer magazine
- No ammunition included
The MR556A1 Competition uses HK's short-stroke gas piston system and includes an ambidextrous safety lever with HK pictogram selector markings. The bolt carrier is laser-etched "HK" and "MR," and the rifle is marked with factory Competition model identifiers on the lower.
The 16.5 in heavy-profile barrel is cold hammer forged, unlined, and free-floated for stability. A 1:7 twist supports a wide range of 5.56mm NATO projectiles, and the helical multi-port compensator provides effective muzzle control.
The 14 in HK MRS extended aluminum handguard features a continuous T-marked Picatinny top rail, keyhole-style slots, and integral QD sling cups. This configuration offers ample mounting real estate along the top rail while keeping the barrel free-floated.
Furniture includes an adjustable 6-position stock with a friction lock and an approximate length of pull from 10.5 to 14 in, plus an HK textured polymer pistol grip. No iron sights are installed.
Markings include "MR 556 A1 COMPETITION 5.56 mm x 45" on the lower, "MR 556 A1 Heckler & Koch Inc. Columbus GA" on the upper, and the HK proof/date code "BH" (2017) with the HK proof symbol. Country of origin is listed as USA/Germany, with importer marking Heckler & Koch Inc., Columbus, GA. Capacity is 30+1 and a 30-round MFT polymer magazine is included.