--- title: "HK USA MR556A1 223/5.56 16.5\" Black 30rd" canonical_url: "https://www.kygunco.com/product/heckler-and-koch-hk-usa-81000579-mr556a1-223-5.56-16.5-black-30rd-or" meta: author: KYGUNCO "og:image": "https://cdn.kygunco.com/assets/products/158522/thumbnail.jpg?v=1712593149" "og:image:height": "500" "og:image:width": "500" "og:title": "HK USA MR556A1 223/5.56 16.5\" Black 30rd" --- > 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-81000579 ![Main product image](https://static.kygunco.com/cdn-cgi/image/f=auto,w=600/assets/products/158522/main.jpg?v=1712593149) For illustration purposes only, this image may not be an exact representation of the product. # HK USA MR556A1 223/5.56 16.5" Black 30rd 5.0 ** ** ** ** ** [1 review](#reviews) $2,890.99 ![Credova logo](https://www.kygunco.com/brands/credova.svg) As low as **$192.84**/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 # 158522 Style HCK-81000579 UPC 642230262553 Condition New Manufacturer [HK USA](https://www.kygunco.com/brand/hk-usa) Model MR556A1 Hand Right Hand Finish Black Round Capacity 30 Caliber 5.56 NATO, 223 Rem Action Semi-Auto Barrel Length 16.5 in A direct descendant of the world-famous HK416, the MR556A1 is the commercial carbine from the same DNA. It offers the battlefield-proven reliability, durability and precision you would expect from a rifle that bears the name Heckler & Koch. The MR556A1 is assembled in the USA using US and German-made components and uses many of the same parts and assemblies developed for the HK416. Like the HK416, the MR556A1 uses a proprietary HK short-stroke gas piston in place of the direct-gas-impingement system found on lesser AR15-style rifles that propels exhaust gas into the upper receiver to operate the action. In the "closed" HK piston system, exhaust gasses never enter the receiver, which means the HK runs cooler, cleaner and more reliably. When adverse conditions, like dust, sand and mud are introduced, the advantage of the HK system becomes even more drastic. That is why so many of the worlds elite military and law-enforcement customers have absolute trust in their HKs. **SPECIFICATIONS** - Action Semi-Auto - Caliber 5.56x45mm NATO - Barrel Length 16.50" - Capacity 30+1 - Safety Manual - Overall Length 37.68" - Weight 8.60 lbs - Stock Adjustable - Muzzle Muzzle Brake - Sights None, Optic Ready - Barrel Medium Contour - Twist 1:7" - Hand Right - Stock Finish Group Black - Metal Finish Group Blued/Black - UPC 642230262553 ** 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). ## Frequently Bought Together 5.0 ** ** ** ** ** 1 review ** ** ** ** ** 1 ** ** ** ** ** 0 ** ** ** ** ** 0 ** ** ** ** ** 0 ** ** ** ** ** 0 ## Reviews ** Johnny Oklahoma City, OK Outstanding rifle. Yes, it cost a lot. But HK demands a premium. And for good reason. Just suck it up and buy it. You won’t be disappointed. 11/21/2023 ** ** ** ** ** ## 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/heckler-and-koch-hk-usa-81000579-mr556a1-223-5.56-16.5-black-30rd-or#webpage","@type":"WebPage","description":"Shop KYGUNCO for firearms, ammo, accessories, parts, and outdoor gear at low prices with fast, easy nationwide shipping.","name":"HK USA MR556A1 223/5.56 16.5\" Black 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