This latest update to the MR556A1 includes an updated grip and forearm as well as a lighter barrel profile that removes nearly a pound of front-end weight from the rifle.
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. That is where that legendary HK reliability comes from.
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 military and law-enforcement elite customers trust HK.
The MR556A1’s barrel is cold hammer forged from the highest quality cannon-grade steel, with a slightly smaller diameter at the muzzle for improved accuracy and velocity. 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.”
- Brand : HK
- Category : Tactical Rifles
- Caliber : 5.56x45mm NATO
- Model : MR556
- Series : A1
- Stock Finish : Black
- Action : Semi-Auto
- Barrel Length Range : 16″ to 16.99″
- Sights : None, Optic Ready
- Capacity : 30+1
- Magazine Type : OEM
- Grips : Black Polymer
- Hand : Right
- Handguards : M-LOK
- OAL : 33.90″-37.68″
- Receiver Finish : Black
- Receiver Material : Aluminum
- Stock Description : Adjustable
- Stock Finish Group : Black
- Stock Material : Synthetic
- Weight : 8.60 lbs
- Barrel Description : Medium Contour
FFL Transfer & Firearms Laws for HK MR556 A1 5.56/.223, 16.5" Medium Contour Barrel, M-LOK, Black, 30rd HK- Heckler and Koch
All firearms, including the HK MR556 A1 5.56/.223, 16.5" Medium Contour Barrel, M-LOK, Black, 30rd HK- Heckler and Koch, 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 A1 5.56/.223, 16.5" Medium Contour Barrel, M-LOK, Black, 30rd HK- Heckler and Koch 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 A1 5.56/.223, 16.5" Medium Contour Barrel, M-LOK, Black, 30rd HK- Heckler and Koch 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 A1 5.56/.223, 16.5" Medium Contour Barrel, M-LOK, Black, 30rd HK- Heckler and Koch?
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 A1 5.56/.223, 16.5" Medium Contour Barrel, M-LOK, Black, 30rd HK- Heckler and Koch 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: 5.56 NATO, Heckler & Koch, RIFLES.
What tags or features does this product have?
Key features and tags for this product include: Guns.
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.
| Classification | Firearm |
|---|---|
| Manufacturer Number | 81000579 |
| Brand | HK- Heckler and Koch |
| interest | AR-15 Rifles |
FFL Transfer & Firearms Laws
All firearms, including the HK MR556 A1 5.56/.223, 16.5" Medium Contour Barrel, M-LOK, Black, 30rd HK- Heckler and Koch, must be shipped to a licensed Federal Firearms License (FFL) dealer. A background check and any required local paperwork must be completed before you can take possession.
How It Works
- Place your order online.
- Send us your preferred local FFL dealer info.
- We ship the firearm to your FFL after verification.
- Complete background check and pick up from your dealer.
Legal Compliance
We comply with all U.S. firearm laws. It is your responsibility to ensure the HK MR556 A1 5.56/.223, 16.5" Medium Contour Barrel, M-LOK, Black, 30rd HK- Heckler and Koch is legal in your state. Some states (e.g. CA, NY, NJ) have restrictions on magazine size or certain features.
Helpful Links
Need help? Contact our team — we’ll guide you through selecting a compliant firearm and the FFL transfer process.
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