Last updated September 25th 2026
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Table of Contents
How we tested: Every pick here is ranked against our testing methodology. Minimum round counts, accuracy and reliability protocols, the failures that disqualify a gun. Where we have not shot a specific variant ourselves, we say so in that section.
The Short Answer
You can’t buy a new HK416. It’s a select-fire military rifle. What you can buy is its civilian twin, the HK MR556, a semi-automatic version with the same short-stroke piston system. And here’s what most articles miss: HK’s own US site no longer lists the MR556A1 that everyone writes about. The current model is the MR556 A4, launched in 2024, and HK lists the rifle at $4,299.
On the street, new A4 rifles we found on September 25, 2026 ran $3,749 to $3,883.99, and leftover A1s were still around from $2,899.99. If you just want the HK416 look and feel for plinking, HK also sells an official HK416 .22 LR built by Umarex, listed at $749 and selling for less.
What the HK416 Actually Is
Take an M4 carbine and replace its direct gas impingement system with a short-stroke gas piston, and you’ve got the core idea of the HK416. Heckler & Koch based the design on the AR-15/M16 family but used a proprietary piston system from its G36 rifle. Instead of piping hot gas back into the receiver, a piston and pusher rod drive the bolt carrier.
HK sums up the payoff on its MR556 A4 page: the piston 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.” If you want the longer version of that trade-off, our best piston AR-15 guide covers the whole category.
Where the HK416 Came From
The rifle started with the US Army’s Delta Force. In the 1990s, at the request of Delta research and development NCO Larry Vickers, the unit worked with Heckler & Koch on a new close-quarters carbine. Delta was carrying the MP5 and the M4. The unit found the MP5’s 9mm too weak and the M4 too large, especially with a suppressor.
The project was first called the HK M4, until Colt Defense filed a trademark infringement suit. HK renamed it the HK416, combining the M4 and the M16. Delta replaced its M4s with HK416Ds in March 2005 after tests showed the piston system cut malfunctions and extended parts life. In 2011, US Navy SEAL Team Six carried the HK416D on the raid that killed Osama bin Laden.
The M27 Infantry Automatic Rifle, the Marine Corps’ HK416 variant, at a National Museum of the Marine Corps storage facility, Marine Corps Base Quantico. U.S. Marine Corps photo illustration by Sgt. James Stanfield, public domain.
Who Uses the HK416 Today
- Norway: adopted the HK416N as its standard-issue rifle in 2008.
- US Marine Corps: adopted a modified variant as the M27 Infantry Automatic Rifle, first to replace the M249 SAW and later the M16A4, M4 and M4A1.
- France: selected the HK416F to replace the FAMAS in 2017.
- Germany: adopted a variant as the G95A1 to replace the G36.
- Ireland: the HK416 A5 is in service with the Army Ranger Wing.
It also turns up in a lot of movies. If that’s how you found it, our breakdown of the guns of The Rip shows it on screen.
Can You Buy an HK416?
Not a real one. The military HK416 is select-fire, which makes it a machine gun under federal law, and new machine guns can’t be registered for civilian ownership. HK’s answer for the civilian market is the MR series. HK introduced the MR556 and MR762 at the 2009 SHOT Show as semi-automatic versions of the HK416 and HK417. In Europe they’re sold as the MR223 and MR308.
The MR556 keeps what matters: the short-stroke piston, the HK barrel, the build quality. What it drops is the full-auto fire control group and, on a rifle, the short barrel. HK does sell an 11 inch SBR version, but that’s an NFA item. It still needs ATF approval and registration before you take it home, even though the federal tax on short-barreled rifles dropped from $200 to $0 on January 1, 2026.
MR556 A4 vs MR556A1: What Changed
The MR556A1 was the civilian HK416 for most of the last 15 years, and it’s still the name most people search. It improved on the original MR556 by moving the takedown pins to the standard location, so its upper receiver fits any M16, M4 or AR-15 family lower.
The MR556 A4 replaced it in 2024 and brings in the updates from the military HK416A7 and A8. HK’s page lists three changes that matter to a shooter: fully ambidextrous controls, a lighter, slimmer profile, and an adjustable gas regulator you can tune for suppressed or unsuppressed shooting. As of September 25, 2026, HK’s commercial catalog lists only A4 versions of the MR series, the MR556 A4 and the .308 MR762 A4, the HK417’s civilian twin. The A1 is gone from HK’s lineup, but dealers still have stock.
MR556 A4 Specs and HK’s Prices
| Model (HK ID) | Barrel | Overall length | Weight (no magazine) | HK MSRP |
| MR556 A4 rifle, 30 rd (81000827) | 16.5 in. | 33.25 to 36.5 in. | 7.67 lb | $4,299 |
| MR556 A4 rifle, 10 rd (81000828) | 16.5 in. | 33.25 to 36.5 in. | 7.67 lb | $4,299 |
| MR556 A4 rifle, CA compliant (81001033) | 16.5 in. | 33.25 to 36.5 in. | 7.67 lb | $4,399 |
| MR556 A4 SBR, NFA (81001048) | 11 in. | 27.9 to 31.7 in. | 7.67 lb | $4,299 |
| MR556 A4 upper receiver kit (51000384) | 16.5 in. | 25.94 in. (upper) | 6.20 lb (kit) | $2,499 |
| HK416 .22 LR rifle (81000401) | 16.1 in. | n/a | 5.7 lb | $749 |
All the MR556 A4s are 5.56 x 45mm with a 1 in 7 inch twist, six lands and grooves, and HK sells its own steel magazines for them. HK lists its 30 round steel magazine at $64.99 and the 10 and 20 round versions at $74.99.
What an MR556 Really Costs in 2026
Nobody pays HK’s list price. Here’s what our catalog showed on September 25, 2026.
- MR556 A4 rifle, 16.5 in.: $3,749 at Classic Firearms and Midway USA, $3,883.99 at Guns.com. That’s roughly $400 to $550 under HK’s $4,299.
- MR556 A4 pistol, 11 in.: from $3,349.99 at Classic Firearms, up to $3,999.99 at EuroOptic.
- Leftover MR556A1: $2,899.99 at Classic Firearms and $3,188.99 at Guns.com, with a CA compliant A1 at $3,195.99.
- 75th anniversary A1 in German camo patterns: $3,994.99 to $4,576.99 at Guns.com.
That makes a leftover A1 about $850 cheaper than a new A4. The live card below tracks the A4 rifle.
Should You Buy a Leftover MR556A1?
For a lot of buyers, yes. You get the same piston system, the same HK barrel and the same reputation for about $850 less. What you give up is the A4’s ambidextrous controls, its slimmer and lighter profile, and the adjustable gas regulator. If you plan to run a suppressor a lot, that regulator is worth paying for. If you don’t, the A1 is the better deal while stock lasts.
Check which one you’re getting before you buy, because plenty of listings still just say “HK MR556.” When I checked, the card below opened at $2,899.99.
How to Tell an MR556A1 From an A4
Listings mix them up constantly, so check before you pay. Start with the left side of the lower receiver: the A4 is marked with the HK logo and “MR 556 A4” above “5.56 mm x 45.” Then look at the controls. HK describes the A4’s controls as fully ambidextrous, so look for controls on both sides of the receiver.
The most reliable check is the HK ID number on the box or in the listing. HK’s current A4 rifles are 81000827 (30 round) and 81000828 (10 round), and the California version is 81001033. A1 rifles in our catalog carried IDs like 81000579 and 81000580. If a seller can’t tell you the ID number, ask for a photo of the receiver markings.
Parts and Magazine Compatibility
One of the best things about the MR556 is how much of the AR-15 world it works with. The MR556A1’s takedown pins sit in the standard location, so its upper fits standard AR-15 lowers without modification, and it runs standard STANAG magazines. The A4 upper receiver kit is built the same way, to fit a Mil-Spec 5.56mm lower.
A few parts are HK-specific. The upper receiver kit ships with HK’s own tungsten-filled buffer and action spring, and those are the ones to run, since HK pairs them with its piston system. The bolt carrier group is HK’s piston carrier, not a standard direct-impingement carrier. Stocks, grips and most lower parts are standard AR fare, which makes an MR556 easy to set up the way you like. Just pick a trigger with a standard full-height hammer, because HK’s firing pin safety needs one.
California and 10-Round States
HK makes it easier than most. It sells a California compliant MR556 A4 with a 10 round magazine, listed at $4,399, which is $100 over the standard rifle, and the standard A4 rifle also comes in a 10 round package (81000828) at the same $4,299. On the street, a California compliant MR556A1 was listed at $3,195.99 at Guns.com on September 25, 2026. Check your state’s rules on features and magazine capacity before you order, because they vary.
The Upper Receiver Kit: HK’s Piston on Your Own Lower
Here’s the option most people don’t know about. HK sells a complete MR556 A4 upper receiver and barrel assembly that bolts onto a Mil-Spec 5.56mm AR-15 lower. The 16.5 inch kit lists at $2,499 and weighs 6.20 lb. It comes with HK’s cold hammer forged barrel, the complete bolt group, HK’s proprietary buffer and action spring, an adjustable gas block and a free-float rail, and HK sells an 11 inch version too.
Better still, HK’s page notes that the upper receiver kit “is not classified as a firearm and can be purchased without a Federal Firearms License.” If you already own a good AR lower, that’s the cheapest way to get a genuine HK piston rifle. Our best AR-15 lower guide can help if you don’t.
The HK416 .22 LR: The Budget Way In
If what you really want is the look and feel, HK licenses an official HK416 in .22 LR, built by Umarex of Germany. HK calls it “the only HK416 .22 LR rifle authorized by HK.” It has a 16.1 inch barrel threaded 1/2 x 28, weighs 5.7 lb without a magazine, and takes 10, 20 or 30 round magazines. HK lists aluminum receivers, a retractable stock, flip-up sights, an M-LOK and 1913 rail system and a last-round bolt hold open.
HK lists it at $749. On the street it’s much cheaper, and the card opened at $511.94 when I checked. For a cheap trainer or a plinker that looks the part, it’s hard to beat. Just don’t expect it to share parts with a real MR556.
Piston AR Alternatives for Less
If you want a piston rifle but not HK money, two guns come up most. The LWRC IC-A5 is a short-stroke piston AR from an American maker, and its card opened at $2,499.99 when I checked, well over $1,000 less than an A4.
The SIG MCX Spear LT takes a different route, with its own short-stroke piston action rather than an AR-15 layout, and a folding stock. Its card opened between $2,299.99 and $2,599.99 across my checks. Neither one is an HK, but both give you the clean-running piston action that makes the HK416 what it is.
Is the MR556 Worth It?
If you want the real thing, yes. There’s no other way to own an HK416-pattern rifle made by HK, and the piston system runs noticeably cleaner than a direct-impingement AR. I’ve shot MR556s, and what stands out is how little carbon ends up in the receiver after a long day, and how solid the whole rifle feels.
But be honest about why you’re buying it. A good direct-impingement AR shoots just as accurately for a fraction of the money, and piston rifles are heavier at the front. If you want the HK name, the military pedigree and the piston system, buy an A4, or a leftover A1 if you don’t need the new controls. If you want the cheapest route to real HK piston parts, buy the upper receiver kit. And if you want the look for plinking, the .22 is a bargain. For a wider view, see our best AR-15 rifles guide.
Specs and MSRPs in this guide come from HK USA’s MR556 A4, upper receiver kit and HK416 .22 LR pages. Street prices are what we saw on September 25, 2026.
Frequently Asked Questions
Can civilians buy an HK416?
Not a real one. The military HK416 is select-fire, which makes it a machine gun under federal law. Civilians can buy HK's semi-automatic version, the MR556, which uses the same short-stroke piston system.
What is the difference between the MR556A1 and MR556 A4?
The MR556 A4 launched in 2024 and brings in updates from the HK416A7 and A8. HK lists fully ambidextrous controls, a lighter and slimmer profile and an adjustable gas regulator for suppressed or unsuppressed shooting. HK's commercial catalog now lists only A4 versions of the MR series.
How much does an HK MR556 cost?
HK lists the MR556 A4 rifle at $4,299 and the California compliant version at $4,399. On September 25, 2026, new A4 rifles ran $3,749 to $3,883.99, and leftover MR556A1 rifles were available from $2,899.99.
Is the MR556 the same as the HK416?
It is the civilian, semi-automatic version. It keeps the HK416's short-stroke gas piston system and HK barrel but drops the select-fire trigger group. HK introduced the MR556 at the 2009 SHOT Show.
Can I put an HK upper on my AR-15 lower?
Yes. HK sells an MR556 A4 upper receiver kit that fits a Mil-Spec 5.56mm AR lower. The 16.5 in. kit lists at $2,499, and HK says it is not classified as a firearm, so no FFL is needed.
Is there a .22 LR HK416?
Yes. HK licenses an official HK416 .22 LR rifle built by Umarex. HK lists it at $749 with a 16.1 in. barrel and a 5.7 lb weight, and it sold for less on the street in September 2026.
Who uses the HK416?
Norway adopted the HK416N as its standard rifle in 2008, France selected the HK416F in 2017, and the US Marine Corps adopted a variant as the M27. Delta Force switched to the HK416D in 2005, and SEAL Team Six carried it on the 2011 raid that killed Osama bin Laden.
Does the MR556 use standard AR-15 magazines?
Yes. The MR556A1 runs standard STANAG magazines, and HK also sells its own steel magazines, listing the 30 round at $64.99.
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