--- title: "HK USA MR556 A4 Black 5.56 NATO Rifle" description: "Black 5.56 NATO rifle with a 16.5\" barrel and 10rd capacity. Features a short-stroke gas piston system, adjustable gas regulator, and ambidextrous controls." canonical_url: "https://www.kygunco.com/product/hk-usa-mr556-a4-5.56-nato-16.5-10rd-black" meta: author: KYGUNCO "og:description": "Black 5.56 NATO rifle with a 16.5\" barrel and 10rd capacity. Features a short-stroke gas piston system, adjustable gas regulator, and ambidextrous controls." "og:image": "https://cdn.kygunco.com/assets/products/270637/thumbnail.jpg?v=1732116383" "og:image:height": "500" "og:image:width": "500" "og:title": "HK USA MR556 A4 Black 5.56 NATO Rifle" --- > 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-81000828 ![Main product image](https://static.kygunco.com/cdn-cgi/image/f=auto,w=600/assets/products/270637/main.jpg?v=1732116383) For illustration purposes only, this image may not be an exact representation of the product. # HK USA MR556 A4 5.56 NATO 16.5" 10rd - Black The HK USA MR556 A4 is a black 5.56 NATO rifle with a 16.5" barrel and 10rd capacity. It uses a short-stroke gas piston operating system, adjustable gas regulator, and fully ambidextrous controls, along with a lighter weight and slimmer profile. $3,749 ![Credova logo](https://www.kygunco.com/brands/credova.svg) As low as **$198.21**/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 # 270637 Style HCK-81000828 UPC 642230269415 Condition New Manufacturer [HK USA](https://www.kygunco.com/brand/hk-usa) Model MR556 A4 Round Capacity 10 Caliber 5.56 NATO Action Semi-Auto Barrel Length 16.5 in 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 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. 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). 0.0 ** ** ** ** ** 0 reviews ** ** ** ** ** 0 ** ** ** ** ** 0 ** ** ** ** ** 0 ** ** ** ** ** 0 ** ** ** ** ** 0 ## 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-a4-5.56-nato-16.5-10rd-black#webpage","@type":"WebPage","description":"Black 5.56 NATO rifle with a 16.5\" barrel and 10rd capacity. 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