Brand: Heckler and Koch (HK USA)
Model: MR556 A4
Caliber: 223 Rem | 5.56 NATO
Barrel Length: 11"
Overall Length: 26.5"
Action: Semi-Auto
Operating System: Short Stroke Gas Piston
Finish: Gray Cerakote
Stock / Grip: HK Enhanced Ergonomic Grip
Twist: 1-in-7"
Capacity: 30rd
Sights: No Sights
Thread Pattern: 1/2x28
Threaded: Yes
Weight: 6.61 lbs.
Safety: Ambidextrous Safety Lever
Receiver: Fully Ambidextrous Lower
Handguard: M-LOK Handguard

Features

The latest update from HK-USA to the commercial variant of the legendary HK416, the MR556 A4, and MR762 A4 represent an enhanced example of “no compromise” HK performance.

Its short-stroke gas piston operating system does not impart hot carbon fouling back into the action, allowing the weapon to run longer, with less maintenance and with less wear on internal components than direct-impingement ARs. Its adjustable gas regulator allows the operator to tune the action specifically for suppressed or unsuppressed operation. Fully ambidextrous controls, lighter weight, and a slimmer profile make the new A4 easier to operate, manipulate, and employ.

For those who demand an AR with unmatched capability and uncompromising reliability and durability, the MR A4s remain the top-tier solution.

HK MR556 A4 – Precision Redefined | Heckler & Koch USA

The HK MR556 A4 represents the pinnacle of precision engineering and tactical performance. Designed for uncompromising accuracy, durability, and reliability, this semi-automatic pistol is a civilian variation of the legendary HK416, trusted by military forces worldwide. With a cold hammer-forged barrel, a gas piston system for cleaner operation, and enhanced modularity, the MR556 A4 is built to exceed expectations in any environment.

Whether you're a competition shooter or a firearm enthusiast, the HK MR556 A4 delivers unparalleled performance and adaptability. Explore advanced features such as the free-floating rail system, ambidextrous controls, and compatibility with a wide range of accessories.

Key Features:

Cold Hammer-Forged Barrel: Ensures long-lasting accuracy and precision.
Gas Piston System: Cleaner and more reliable operation compared to direct impingement systems.
Enhanced Modularity: Customizable rail system for attaching optics, grips, and other accessories.

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It is the customer’s responsibility for understanding state laws regarding all purchases made. For a comprehensive list of all Shipping Restrictions, please refer to our Shipping Restrictions By State Page found Here.

All NFA Rules Apply

These items are controlled by the U.S. Government and authorized for export only to the country of ultimate destination for use by the ultimate consignee or end-user(s) herein identified. They may not be resold, transferred, or otherwise disposed of, to any other country or to any person other than the authorized ultimate consignee or end-user(s), either in their original form or after being incorporated into other items, without first obtaining approval from the U.S. government or as otherwise authorized by U.S. law and regulations.

Magazines will be removed from firearms when shipping to states with magazine capacity restrictions.

California 10+ Round Magazine Buyers: PSA values your freedom and constitutional rights above all else. However, PSA will not accept new orders nor will ship any order until the Ninth Circuit Federal Court of Appeals mandate becomes finalized. Once this mandate is finalized, we will start accepting new orders and ship 10+ round magazines to California Customers.

WARNING: Handling firearms or firearms parts can expose you to lead and other petroleum products known to the State of California to cause cancer, birth defects, or other reproductive harm. Wash hands thoroughly after handling. For more information go to www.p65warnings.ca.gov (CA Health and Safety Code Section 25249.6).