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 world’s elite military and law-enforcement customers have absolute trust in their HKs.
The MR556A1’s barrel is cold hammer forged from the highest quality cannon-grade steel. It has a 1 in 7” twist and a taper-bore configuration, with a slightly smaller diameter at the muzzle for improved accuracy and velocity. And while the material and cold hammer forging process themselves greatly enhance durability, HK’s processes include many additional steps not taken by other manufacturers to produce superior accuracy and service life, ensuring performance well beyond “mil-spec.”
- Safety : Manual Safety
- Frame Finish : Black
- Weight : 8.6 lbs.
- Firearm Stock : Black Synthetic Adjustable
- Features : Hellfighter MOD Kit
- Finish : Black
- Magazine Count : 1
- Operating System : Gas Piston
- Firing System : Internal Hammer
- Scope Base : Picatinny Rail
- Trigger : 2-Stage
- Magazine Type : Double Stack Magazine
- Barrel Configuration : Single
- Barrel Description : Medium Contour
- Threaded Barrel : Yes
- Rifled Barrel : Yes
- Forend Rail : Free Float 4 Quadrant Rail
FFL Transfer & Firearms Laws for HK MR556 5.56x45mm, 16.5" Barrel, Black, CA Complliant, 10rd
All firearms, including the HK MR556 5.56x45mm, 16.5" Barrel, Black, CA Complliant, 10rd, must be shipped to a licensed Federal Firearms License (FFL) dealer. You will be required to complete a background check and any necessary paperwork before taking possession.
How It Works
- Place your order online.
- Provide your preferred FFL dealer information.
- We ship the firearm directly to your FFL.
- You complete the background check and pickup at the FFL.
Legal Compliance
We comply with all federal and state firearm laws. It is your responsibility to ensure the HK MR556 5.56x45mm, 16.5" Barrel, Black, CA Complliant, 10rd is legal in your state. Some states may have restrictions on certain firearm models or features.
Helpful Resources
Need assistance? Contact our Miami store for help with FFL transfers and firearm compliance.
Frequently Asked Questions About This Product
Why buy HK MR556 5.56x45mm, 16.5" Barrel, Black, CA Complliant, 10rd from Miami Shooters Supply?
We’re a trusted firearms dealer offering fast shipping, competitive pricing, and 100% compliance with U.S. federal firearm laws. All orders ship from our licensed facility with full tracking and expert customer service.
Where can I buy HK MR556 5.56x45mm, 16.5" Barrel, Black, CA Complliant, 10rd?
You can purchase this item directly on our website and have it shipped to your local FFL dealer. You can also visit us in-store in Miami, Florida.
Is HK MR556 5.56x45mm, 16.5" Barrel, Black, CA Complliant, 10rd available now?
Availability is shown live on this page. If the “Add to Cart” button is visible, this item is currently in stock and ready to ship.
What category does this product belong to?
This product is listed under: California, Firearm, Home Defense Guns.
What tags or features does this product have?
Key features and tags for this product include: : Black Synthetic Adjustable, Firearm, HK MR556, HK- Heckler and Koch.
Is this product legal in my state?
It is your responsibility to ensure this item is legal in your state or locality. We ship only to valid FFL dealers in compliance with U.S. laws. Always check your local regulations.