--- title: "HK MR556 A4 5.56 11\" 30rd Black" description: "Compact 5.56 rifle with an 11\" cold hammer-forged barrel and HK piston system. Clean-running, reliable, and built for high-performance use." canonical_url: "https://www.kygunco.com/product/hk-usa-mr556-5.56x45-11-30rd-black" meta: author: KYGUNCO "og:description": "Compact 5.56 rifle with an 11\" cold hammer-forged barrel and HK piston system. Clean-running, reliable, and built for high-performance use." "og:image": "https://cdn.kygunco.com/assets/products/289552/thumbnail.jpg?v=1750357348" "og:image:height": "500" "og:image:width": "500" "og:title": "HK MR556 A4 5.56 11\" 30rd Black" --- > Index of every page on this site: [llms.txt](https://www.kygunco.com/llms.txt) [Home](https://www.kygunco.com/) / [Shooting](https://www.kygunco.com/category/shooting) / [Guns](https://www.kygunco.com/category/shooting/guns) / [Rifles](https://www.kygunco.com/category/shooting/guns/rifles) / [Semi-Auto](https://www.kygunco.com/category/shooting/guns/rifles/semi-auto) / HCK-81001201 ![Main product image](https://static.kygunco.com/cdn-cgi/image/f=auto,w=600/assets/products/289552/main.jpg?v=1750357348) For illustration purposes only, this image may not be an exact representation of the product. # HK USA MR556 A4 5.56x45mm 11" 30rd - Patriot Brown The HK MR556 with an 11" barrel is a compact premium 5.56x45mm rifle based on the HK416 design. It uses HK’s short-stroke gas piston system for cleaner operation and exceptional reliability, even in demanding conditions. The cold hammer-forged barrel, free-floated handguard, and robust upper and lower receivers support precise, consistent performance in a maneuverable platform suited for tactical or range use. 5.0 ** ** ** ** ** [1 review](#reviews) $3,621.45 ![Credova logo](https://www.kygunco.com/brands/credova.svg) As low as **$191.47**/month with ![Credova text logo](https://www.kygunco.com/brands/credova-text.svg) ** Online In Store ** Free Shipping Enjoy delivery to the Lower 48 States at no cost. ** Ships To FFL Dealer Handled by our expert shippers in Bardstown, KY. ** Check Local Restrictions Not sure whether this item can be shipped to your area? Enter your ZIP code for a quick check. Item # 289552 Style HCK-81001201 UPC 642230271050 Condition New Manufacturer [HK USA](https://www.kygunco.com/brand/hk-usa) Model MR556 Round Capacity 30 Caliber 5.56 NATO Action Semi-Auto Barrel Length 11 in The legendary HK gas piston system reduces fouling and heat transfer into the receiver, making the MR556 ideal for demanding shooting environments. A **cold hammer-forged, 6-groove barrel** with a 1:7” twist enhances accuracy and barrel longevity, while the **M-LOK handguard** provides lightweight modularity for accessories. The ambidextrous controls—including the safety selector and charging handle—make this a versatile option for both right- and left-handed shooters. The **6-position adjustable synthetic stock** allows for a customized fit and stable shooting stance, even in dynamic situations. A full-length **Picatinny rail** on the receiver offers optimal space for optics, irons, or laser modules, and the lack of factory sights gives you freedom to configure as needed. With its **smooth 4.5–5.6 lb trigger pull** and sleek design, the MR556 A4 offers exceptional control, durability, and battlefield-proven engineering. - Stock Type: 6-Position Adjustable - Stock Material: Synthetic - Grip: Black Polymer - Handguard: M-LOK - Trigger Pull Weight: 4.50 – 5.60 lbs - Safety: Ambidextrous Safety Lever - Sights: None (Optics Ready) - Overall Length: 26.50" - Height: 7.50" Shop with KYGUNCO for the best selection, competitive pricing, and exceptional customer service. Experience the difference that comes with buying from a trusted outdoor retailer with over 20 years of experience in the industry. ** WARNING: This product contains chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information, go to [www.p65warnings.ca.gov](https://www.p65warnings.ca.gov). 5.0 ** ** ** ** ** 1 review ** ** ** ** ** 1 ** ** ** ** ** 0 ** ** ** ** ** 0 ** ** ** ** ** 0 ** ** ** ** ** 0 ## Reviews ** Verified Customer Great transaction. 12/11/2025 ** ** ** ** ** ## Don't Forget Your Ammo ```json {"@context":"https://schema.org","@graph":[{"@id":"https://www.kygunco.com/#website","@type":"WebSite","description":"Shop KYGUNCO for firearms, ammo, accessories, parts, and outdoor gear at low prices with fast, easy nationwide shipping.","name":"KYGUNCO","url":"https://www.kygunco.com/","publisher":{"@id":"https://www.kygunco.com/#/schema/organization/kygunco"}},{"@id":"https://www.kygunco.com/product/hk-usa-mr556-5.56x45-11-30rd-black#webpage","@type":"WebPage","description":"Compact 5.56 rifle with an 11\" cold hammer-forged barrel and HK piston system. 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