HK MR556 A1 for sale
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HK MR556 A1 5.56/.223, 16.5" Medium Contour Barrel, M-LOK, Black, 30rd
Brand:
HK
Action:
Semi-Auto
Barrel Length:
16.5in
Caliber:
5.56×45mm NATO
Capacity:
30+1
Finish Per Color:
Black
Marketplace Insights
★ 3.8/5
based on 4 customer reviews across 2 variants from 19 retailers
Generally positive reviews praising weapon quality and performance, with isolated concerns about product condition and included accessories.
What customers like
High quality weapon75%
Very high quality rifle that is the personal weapon of a SEAL friend
Reliable performance50%
HK MR556A1 is the real deal hands down
Good customer service50%
Service was easy and quick
Common concerns
Product condition issues25%
Rifle was not new. -Bag had broken strap. -Handguard was marred
Non-OEM accessories included25%
came with a Magpul magazine and hand grip instead of HK parts
Frequently Asked Questions
HK MR556 A1 for sale
How reliable is the MR556A1?
The MR556A1 is highly reliable. It uses HK's proprietary piston system, which runs cleaner and cooler than direct-impingement ARs. It functions consistently across various ammunition and conditions with minimal malfunctions. Most reliability complaints stem from user error or poor maintenance rather than mechanical deficiencies.
What is the difference between HK416 and MR556A1?
HK416 is a military select-fire rifle; MR556A1 is its civilian semi-automatic counterpart. The HK416 has chrome-lined barrels, vented gas blocks, and ambidextrous controls (A5 variant), plus sling loops. The MR556A1's non-chrome-lined barrel is actually considered superior for accuracy, as chrome lining can mask imperfections. Both chamber 5.56 NATO/.223 Remington.
What makes the HK MR556 unique?
The current HK MR556 A4 uses a short-stroke gas piston system derived from the HK416, running cleaner than direct-impingement ARs. It features a new MLOK forend rail design, a two-position gas block, fully ambidextrous controls, and a thinner, lighter handguard than previous MR556 versions.
Does the MR556A1 have ambidextrous controls?
Yes, the MR556A1 does have ambidextrous controls. It features ambidextrous selector/safety levers on both sides of the lower receiver, along with a reversible charging handle. We currently have several MR556A1 listings on our marketplace for buyers seeking this versatile rifle.
What are the differences in MR556 models?
HK offers two MR556 variants. The A1 ships with an HKey MRS fore end, replacing the older quad-rail design. The new-for-2025 A4 adds fully ambidextrous controls, a more conventional magwell angle, and upgraded furniture, available in 11.5-inch pistol and 16.5-inch rifle configurations. Both fire 5.56 NATO semi-auto with 30-round capacity.
Is the HK MR556 upper compatible?
HK MR556 uppers are compatible with standard AR-15 lower receivers, including previous MR556 generations. HK sells complete upper kits separately. If building from mixed parts, verify your configuration meets 922r compliance requirements.
Why is the HK MR556 so expensive?
HK MR556 rifles command premium pricing due to their short-stroke piston system, cold hammer-forged barrels, ambidextrous controls, and German manufacturing standards. Limited production volumes prevent economies of scale, and proprietary components don't interchange with standard AR parts, eliminating cheaper aftermarket alternatives.
What are the reviews of the HK MR556?
Reviewers praise the MR556 for accuracy, reliability, and build quality. Its cold-hammer-forged barrel and piston-driven system receive consistent approval. The current A4 model weighs 7.5 pounds, significantly lighter than earlier versions that approached 9 pounds, addressing past weight criticism. Its $3,000–$3,500 price still draws value comparisons to cheaper alternatives.
How much is an MR556A1?
MR556A1 rifles typically cost around $3,199, with most listings ranging from $2,690 to $3,499. The premium reflects Heckler & Koch's German manufacturing, cold hammer-forged barrel, and short-stroke piston system.
Is the HK MR556 barrel chrome lined?
HK factory MR556 barrels are cold-hammer-forged 4150 chromoly steel and are not chrome-lined. Chrome lining was a military requirement for the HK416, not the civilian MR556. Aftermarket chrome-lined barrels for the MR556 platform are available from third-party manufacturers.
Is chrome-lined barrel better than not?
Chrome-lined barrels resist corrosion and last longer under heavy use, making them ideal for military or high-volume shooting. The tradeoff is slight accuracy loss versus match-grade barrels. For most civilian shooters, this difference is negligible. Stainless steel barrels offer similar durability with better accuracy potential.
Where is the HK MR556 manufactured?
Heckler & Koch manufactures MR556 upper receivers and barrels in Germany. Final assembly occurs in the USA using US and German-made components, with most manufacturing handled by third-party suppliers. Newer MR A4 series production also involves HK USA making certain components in Columbus.
What is the weight of the HK MR556?
The HK MR556 weighs approximately 7.67 pounds (3.48 kg) unloaded without a magazine. Weight varies significantly between variants — the A4 model weighs around 7.5 pounds, while earlier predecessors weighed nearly 9 pounds, a major reduction achieved through a barrel profile change.