HK MR556 A4 5.56 NATO Black Rifle

Description

Product Overview

The HK MR556 A4 is HK’s commercial 16.5-inch MR416-style rifle built around a short-stroke gas piston system. It’s designed to reduce hot carbon fouling returning into the action while supporting longer run-times with less maintenance compared to direct-impingement designs. A 2-position adjustable gas regulator lets you tune the system for suppressed or unsuppressed use, and the fully ambidextrous control layout makes it easy to operate and reload from either side.

Key Features

• Short-stroke gas piston system for cleaner operation and reduced fouling in the action
• 2-position adjustable gas regulator for tuning suppressed or unsuppressed setups
• Suppressor-ready 1/2x28 concentric threads for common rifle suppressor mounting
• Fully ambidextrous controls including safety selector, bolt release, and magazine release
• Continuous Picatinny rail interface and M-LOK handguard with integral ambi QD cups
• Cold-hammer-forged barrel for durability and consistent performance

If you want an AR-style rifle platform with piston reliability and HK-level durability, the MR556 A4 delivers a modern configuration ready for your optics and accessories.