Heckler and Koch MR556 A4 5.56 Semi-Automatic Pistol

Overview

The Heckler and Koch MR556 A4 represents a precision-engineered short-barreled platform, leveraging the robust and reliable architecture of the HK416 system. Designed for high-demand applications, this semi-automatic pistol delivers consistent performance and exceptional durability in a compact footprint. Its design priorities include operational reliability, reduced maintenance, and uncompromised structural integrity, making it a professional-grade solution.

Key Features

Short-Stroke Gas Piston System

The MR556 A4 employs HK’s proprietary short-stroke gas piston operating system, a significant technical departure from direct impingement designs. This system effectively redirects combustion gases away from the bolt carrier group and receiver, substantially reducing carbon fouling and mitigating heat transfer. The result is enhanced reliability across diverse ammunition types and environmental conditions, extended component service life, and a cleaner, cooler operating cycle. This design also contributes to a more consistent recoil impulse.

Cold Hammer-Forged Barrel

The 11-inch barrel is cold hammer-forged from high-grade steel. This manufacturing process densifies the barrel steel, creating a bore with superior concentricity and uniform land and groove dimensions. The outcome is exceptional long-term durability and sustained accuracy, even under high rates of fire. The free-floating barrel design further optimizes inherent precision by eliminating contact points that could introduce harmonics and affect shot placement.

Robust Construction and Finish

Engineered with an unwavering focus on durability, the MR556 A4 features meticulously machined upper and lower receivers constructed from high-strength aluminum alloy. This ensures precise component fitment and structural integrity capable of withstanding rigorous operational demands. The applied gray finish provides a resilient, low-reflection surface treatment that enhances corrosion resistance and contributes to the platform’s overall longevity.

Ergonomic Integration

The MR556 A4 maintains critical AR-pattern interface compatibility for accessories, facilitating extensive customization. The forend integrates Picatinny accessory rails for secure attachment of optics, illumination devices, and other mission-essential equipment. Controls are intuitively placed to minimize user training requirements and support rapid, efficient manipulation under stress.

Technical Specifications

Caliber

5.56x45mm NATO (.223 Remington compatible)

Operating System

Short-Stroke Gas Piston

Barrel Length

11 inches

Capacity

10+1 rounds (supplied with one 10-round magazine)

Finish

Gray

Receiver Material

High-Strength Aluminum Alloy

SKU

LIP|HK81001313