Heckler & Koch MR 556 A4 Pistol, 5.56 NATO, 11 in Barrel, Short-Stroke Piston, M-LOK, Excellent Condition
This HK MR 556 A4 pistol stands out with an 11-inch, steel, threaded barrel on a short-stroke gas piston system and a two-position gas regulator marked N/S for suppressed or unsuppressed settings. It features ambidextrous controls, a slim free-float M-LOK aluminum handguard with a T-marked full-length Picatinny top rail, an HK-marked bolt carrier, and an SB Tactical adjustable stabilizing brace. It comes in excellent condition with a clean, shiny bore and includes an HK-branded soft case, the original case and manual, a 30-round PMAG, and an installed M-LOK angled hand stop.
Condition
Overall Condition: Excellent condition, showing only faint signs of any prior use or handling.
Bore Condition: Excellent - Clean, mirror finish, no signs of wear.
Rifling: Excellent - Sharp lands and grooves.
Specific Condition Notes: Shows minimal prior handling. The bore is bright with a mirror finish.
What’s Included
- HK-branded soft case (black)
- Original case
- Original manual
- 1x 30-round Magpul PMAG AR/M4 GEN M3 polymer magazine
- M-LOK angled hand stop (installed)
The short-stroke gas piston action with a two-position regulator labeled N/S is designed for reliable cycling in both suppressed and unsuppressed configurations. The HK-marked bolt carrier complements this system and reflects factory components throughout.
The 11-inch, threaded steel barrel is capped with an open-tine, four-prong flash hider. The slim, free-float M-LOK aluminum handguard includes HK and shield CF marks and integrates a T-marked full-length Picatinny top rail that is continuous with the receiver.
Ambidextrous controls include the safety selector and a charging handle with large bilateral latches for confident manipulation. The pistol wears a matte black anodized receiver finish with a matching overall matte black appearance.
Ergonomics are handled by an SB Tactical adjustable stabilizing brace with a QD sling socket and an HK-pattern polymer pistol grip with finger grooves. The firearm accepts standard AR-15/M16 magazines and ships with a 30-round PMAG.
Receiver markings read Heckler & Koch Inc., Columbus, GA, confirming U.S. manufacture. This MR A4-series, AR-15-platform pistol is a recent-production example in excellent condition.