Rifles > Semi-Auto

SIG Sauer 556R

With its mild recoil and rugged, compact platform, the 556R is a well-made rifle for the 7.62x39 mm round.


With a history dating back to just after the end of World War II as the standard military platform used by the former Soviet Union, the AK-47 served as a symbol of communist aggression behind the Iron Curtain. Considered one of the earliest assault rifles, the AK, and its variants, is chambered in 7.62x39 mm, and while it has been accused of being ugly, it is extremely reliable.

There are many countries where the AK and its chambering is still in use, though some have relegated  both to reserve status, preferring to use standard NATO rifle and cartridge designations. There are, however, untold amounts of military surplus 7.62x39 mm ammunition, making it one of the most commonly available rounds in the world. Because of this manufacturers have entered into this market and developed rifles in this chambering, such as the SIG Sauer 556R.

The 556R is built on the same rotary bolt, two-position adjustable-gas piston system as the 5.56x45 mm versions that have been available since shortly after SIG built its New Hampshire plant. The two-position gas valve allows the gun to be adjusted to continue running when dirty or being used in adverse conditions. This system also allows the stock to be folded toward the ejection port, without blocking the port during firing, to provide a more compact rifle platform for use in tight spaces, while also offering a full-length stock that can be quickly flipped into place for more support.

The forearm, butt stock and pistol grip of the 556R are made of black polymer, while the metal components are covered in a matte-black finish that is evenly applied, providing coverage and protection for all parts. Some of the well-thought-out extras include an ambidextrous safety, a spring-loaded trigger guard for accommodating gloved fingers and storage in the pistol grip.

Disassembly is simple, though it does include numerous steps. First, remove the AK-style magazine and ensure the firearm is unloaded. Then press the rear take-down pin from the left side and pull it to the right until it stops before pressing the pivot pin in the same way. From here the top receiver will lift off of the trigger housing. Depress the charging handle catch and remove the charging handle. Use the charging handle to push the bolt carrier to the rear and remove it from the receiver. Rotate the bolt head counterclockwise until the lug clears the cam and separate the units. Remove the firing pin from the bolt head by depressing the pin and knocking out the stud with a punch (be careful not to let the firing pin shoot out under pressure from the spring).

The dual-piece forearm is removed by pulling back and down on the lower piece and lifting the upper away from the gas block. Remove the gas valve by depressing the pin on the left side and rotating the unit to the left and removing, which allows the operating rod assembly to come out. Then, depress the pin on the left again and rotate the gas tube 90 degrees and lift.  Anything further should be done by a qualified gunsmith. Reassembly is done in reverse.

Once back together, SIG recommends a function test by, once again, ensuring the rifle is unloaded and pulling the reciprocating charging handle to the rear and allowing it to go back into battery. Put the safety lever on “safe” and pull the trigger. The hammer should not drop. Turn the lever to “fire” and pull the trigger. The hammer should fall. Finally, hold the trigger to the rear and cycle the charging handle. The hammer should not drop when the gun returns to battery, but should when the trigger is released and pressed.

Range work began with the included SIG Sauer red-dot optic. The red dot was easy to mount and sight in, and exhibited decent self-defense accuracy. At ranges between 25 and 100 yards, center mass hits were obtained during drills, and groups shrank considerably when using supported shooting positions, such as kneeling, prone and barrier. However, since the optic is only 1X, I would have preferred iron sights for durability and to eliminate the need for a battery. SIG Sauer offers aftermarket iron sights, as do some other companies, but they don’t come standard.

Its unloaded weight of 7 pounds and mild 7.62x39 mm chambering, provided very little recoil and allowed fast follow-up shots during multiple target strings. Even when firing with the butt stock in its forward position recoil was manageable, though accuracy suffered greatly, and the rifle ran with zero problems throughout testing. The trigger, however, was of the typical battle type, with significant take up and a fairly heavy trigger pull at just over 7 pounds. The pistol grip was comfortable and fits most hands well, though smaller hands might have a problem reaching the safety mechanism, and the forearm was easy to hold and never became hot, regardless of the number of rounds fired.

For formal accuracy testing, I mounted a Night Force 2.5-10x24 NSX riflescope on quick-detach mounts and settled the gun into a Caldwell Fire Control rest with two Winchester loads and one Tula steel-case load. Accuracy was decent, but not spectacular in five-shot groups with the Winchester 123-grain soft point loads averaging 2.34 inches and the Winchester 123-grain FMJ averaging 2.5 inches. However, I noticed throughout the process that three-shot groups stayed right at the 1-inch mark, with the fourth and fifth shots adding significant spreading in the groups. In a couple of groups, it was the fifth round that increased the spread. The Tula 122-grain FMJ load fared similarly with multiple three-shot groups measuring just a little over an inch, while five-shot groups spread out into the 2 and 3 inch ranges. The Winchester soft points had multiple, three-shot groups that measured under an inch, and was determined as the best load during the testing procedures.

The 556R comes with a single 30-round magazine of the AK variety. It is made of polymer in Bulgaria, and was easy to work with throughout testing, securely fitting into the magazine well, with fast removal. The magazine was quite durable as it was dropped several times during testing, and showing no sign of breakage, and like the AK, the bolt doesn’t lock open on the magazine with the last round. Since most standard AK magazines should work with the 556R, only one metal magazine was tested, the lack of an additional magazine isn’t a huge problem, but it would be nice to have at least a second magazine come with the rifle.

Overall, the SIG Sauer 556R performed admirably, and is excellent for what it is intended—a better-made rifle for firing the 7.62x39 mm caliber round. It is a fighting and self-defense rifle, not a sub-m.o.a. precision rifle. It is fun to shoot, and would work well on large targets out to a few hundred yards, while excelling on fast-action, close-range targets, with what could arguably be the most plentiful round in the world.

Manufacturer: SIG Sauer; www.sigsauer.com
Caliber: 7.62x39 mm
Action: semi-auto, rotary bolt, two-position adjustable-gas piston
Receiver: aluminum
Barrel: 16”
Rifling: 1:9.5” RH twist
Magazine: single 30-round polymer
Sights: none; mini red-dot sight
Trigger: 7.15 lbs.
Stock: polymer
Overall Length: 35.875”; folded 26”
Weight: 7 lbs. without magazine
Accessories: lock; 1” butt plate extension; hand guard rail kit for mounting accessories
Suggested Retail Price: $1332

SIG Sauer 556R

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18 Responses to SIG Sauer 556R

RevLee wrote:
July 07, 2014

I just got my 556R and also ordered 2-10 round and a 20 round mags from Brownells. The 10 rounders make it easier in my rest and they all shoot flawlessly. I love the feel. It is a Sig.

TTacoma wrote:
May 09, 2014

Had mine for awhile, only shot once so far put a couple hundred rounds through it. I love it, have a eotech, and leopold pig plex 1x4 with quick disconnects, buis, Troy diamond rear, samson front. gripod, will be shooting much more this summer. Bought for SHTF, plinking, and because love the round, and all around design, best intermediate round gun out there in larger caliber IMO...for what thats worth

Boots wrote:
April 28, 2014

Love my 556R. Trigger was heavy at first, but its just fine now. It's one of my favorite rifles to play with. I bought it for hog hunting and camp defense (South Texas) I'm not worried.

Curt wrote:
March 10, 2014

I have a M-556-R that is minus the flash suppressor, as it was made for some states 'special regulation'. I find the fit, finish, and accuracy superb. I am not disappointed at all. Shoots all rounds reliably and accurately. I would be shocked if there were ever any issues with Sig's quality. I only purchased the Sig in 7.62 when the 5.56 ammo disappeared in 2013. Now I have the best of both worlds in my gun safe. The M-556’s folding stock and compactness does make it much more amenable than the M4 when getting in and out of the truck quickly. As with anything, they both have their pros and cons, but the M-556-R has been duly weighed, measured, and found worthy.

Jim wrote:
December 27, 2013

I am currently going the the California DROS for this gun. Because Riflegear only had AW's that were not converted to California legal, I had to purchase this gun site unseen. Once they 'fixed' it to Cali standards, I went in to examine it, and noted that there was slight play between the upper and lower receivers. I showed this to the Riflegear salesman, who opined that it was 'completely normal'. I explained that NO rifle that I had EVER owned had any play in it. I noted: not IMI Galil, German HK 91, 3 Colt AR 15's, DSA Fal, or my current Springfield M1A. I believe that salesman was flaunting his ignorance, and trying to con me. Have any of you found play between the upper and lower receivers on your Sig 556R's or any Sig 500 series? My DROS is not yet complete, and I understand that Sig America had problems with the Gen 1 series. Any comments? A $1500 gun should not have this play! Is Sig's QC that bad?

John W wrote:
November 01, 2013

very bought our our 556R for self defense and hog hunting. No issues of any kind using a variety steel case and brass ammo. The rifle is well built and handles well. very pleased with this Sig rifle.

John wrote:
October 30, 2013

I purchased my 556R and tried to shoot but after 1 shot it wouldn't eject spent shells. Same thing after multiple attempts and adjusting the piston setting. Had to send it back to Sig and after 3 weeks had it again. This time it worked flawlessly on brass and steel ammo. The gun's accuracy is better than mine at 100 yards, it has excellent quality (once fixed) and was a good buy excepting that mine didn't come with the red dot optic - think the large dealer kept it. I think Sig calls it the 556R rather than 762 because of the legacy of the Swiss 55x series, which the overall quality earns.

Exseabee wrote:
October 02, 2013

I don't care what you call it. The Sig 556R or 7.26. It works GREAT for me. As long as it works and continues to work as it does. GO WITH IT.

Tony Thompson wrote:
September 14, 2013

Just picked up the Sig 556R Gen 2 and would like to put all the bad BS hype to bed. Cycled 210 rounds of mixed 762X39 clean with no problems. ZERO ISSUES!! Tul, Golden Tiger, WPA and Wolf. All kicked butt!! Would def kerp this in my SHTF arsenal.

Thomas wrote:
July 31, 2013

I like mine, no jams works fine every time.

Ernie wrote:
July 30, 2013

Geez. First of all, the 'R' designates Russian. It's a SIG556 'Russian' model. Secondly, the rilfe will accept any magazine that holds the 7.63x39 round. You are not forced to use what came with it, i.e., plastic magazines. There are several good reviews online that test mutiple mags. Excellent rifle, btw.

Mark wrote:
July 29, 2013

I'm with cbunix23. Wouldn't it have made sense to call it the SIG762R. And what does the 'R' mean exactly. I'm sure there won't be any confusion. 'Hey, you got one of the those SIG556's yet?' 'Yeah, we do. Which one do you want?' 'The SIG556. Did I stutter?' 'No sir. What caliber do you want?' 'I said SIG556, didn't I?'

jimbob wrote:
July 22, 2013

Have one on order. read for it to arrive. Anticipation level very high!!

kelly harbeson wrote:
June 26, 2013

A Kalashnikov reverse engineered by watchmakers. If only Sig had built that gun in 5.45x39.

KK357SIG wrote:
June 18, 2013

Now I know what happens when an AK and FN-FAL are together alone. A win for the USA!

Erik wrote:
June 18, 2013

I purchased my 556r earlier this spring and my friends and I have been having a ball with it. Just as stated by author the low recoil makes the 556r a joy to shoot and you should see the smiles when someone shoots it for the first time from the hip with the stock folded! Hard to have much more fun than that.

BPH9 wrote:
June 17, 2013

I have been thinking of buying one of these but I just wish you could get metal magazines instead of the plastic one that it comes with.

cbunix23 wrote:
June 17, 2013

What genius came up with that model number?