SIG SAUER 556R Rifle
Travis Pike for TTAG
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The SIG 556 rifles didn’t have a great run in the United States. They lasted around ten years and came in various calibers and configurations over that time. They died an uneventful death in 2017. Throughout their lives, they were plagued with issues.

Early guns had accuracy and reliability issues and weren’t well regarded, especially for the price. Regardless, as a fan of firearms that aren’t AR-15s, I knew I had to have one. As a guy with a ton of AK magazines and ammunition, I knew I wanted the SIG 556R. 

The R stands for Russian. The SIG 556R was designed to be an AK replacement that could utilize AK magazines and AK ammo without issue. It gave you AK power and common magazine patterns with a more modern and modular platform.

I liked that idea, and I like weird guns. SIG made a few different variants of the 556 rifle, and this includes the Xi, the SWAT, and more I won’t list here. 

SIG SAUER 556R rifle
(Travis Pike for TTAG)

SIG 550 History

The SIG 550 series have rifles that have been serving the Swiss military for some time and they seem to be doing so successfully. The 550 series is a weird amalgamation of parts and pieces from other guns. The long-stroke gas piston is very AK-like, and the receivers split into halves like an AR or FAL design. 

The guns feature a manually adjustable gas valve that has two settings. One is normal, and the other is for adverse situations in which the weapon is heavily fouled. The trigger guard pivots to accommodate gloved hands for use in those chilly Swiss alps. An attachable grenade launcher is also an option. 

Various models were produced, and the original 550 used a 20-inch barrel, the 551 uses a 14.3, and the 552/553 Commando variants were equipped with a short 8.9-inch barrel, and lastly, the SIG 550 Sniper wore a 25.6-inch barrel.

The SIG 553R is the precursor to the 556R and was designed with export in mind. However, I’m unable to find any actually adopted and used anywhere in the world. The 5.56 variants served across the Swiss military and various other military forces around the globe. 

The SIG 550 series has served far and long from UK police forces to the Swiss Guard at the Vatican. It’s in serve across Asia, East Europe, and even one of my favorite countries ever, Malta. 

The original 550 series utilized a proprietary polymer magazine. Those magazines could Jungle clip together based on their design and came in 20 and 30 round variants. It seems at some point some real SIG 551A1s were imported and used the original Swiss magazines. 

The new SIG 556 series utilized AR magazines, and as mentioned, the 556R used standard AK magazines. 

Hands-on with the 556R

With some horse-trading, I was able to acquire a SIG 556R classic model. The classic model wasn’t fancy. It has a right hand only charging handle, a stock I am not impressed with, and usually, the guns do not have rails for accessories.

Since I was trading on the second-hand market, I found a SIG 556R equipped with a Troy quad rail. It was a little heavier, but the rail increases modularity even more. I also tacked on a set of LPA sights designed for a CZ Scorpion, and they worked like a charm. 

The stock feels rather cheap. It does collapse as well as fold. When you try to extend the stock, it will often just pop off the receiver extension. The cheek weld isn’t great like the Xi model, and the 556 rifles really should have used the classic Swiss style stocks. 

These stocks aren’t impressive (Travis Pike for TTAG)

Admittedly the gun gave me some jamming issues. I was disappointed, so I reached out to SIG, and they charged me for the return tag, and it was off. A few weeks later, I had my rifle back at no further charge, and it worked like a champ. I do appreciate SIG’s customer service, and the gun has been running problem-free for years. 

After SIG fixed it, the gun ate every cheap load of ammo I could put through it. The AK is a gun produced by so many across so many different countries that magazine compatibility can be tricky. Oddly enough, the SIG 556R can seemingly run with every magazine I’ve put through it. This includes Romanians, Koreans, Chinese magazines, Yugos, Magpuls, Tapcos, and more. The SIG 556R even works with the last round bolt hold open on Yugo magazines. The only magazines not compatible are drum magazines.

Get a Grip 

The controls are well placed to me and for my big hands. The safety is ambidextrous and is head and tails above a standard AK controls. The right side charging handle is well suited if you are already a fan of AK style charging handles and used to reach under or around to access it. 

I also love the big pistol grip. It reminds me of a SAW pistol grip. It’s vast and easy to grip and fills my hand well. The stock LOP is just right for me, and while I typically don’t like the stock, it does have a comfortable length of pull. 

Love the stock, and the safety is much better than an AK (Travis Pike for TTAG)

Yeah, the trigger admittedly sucks. This two-stage design takes a hair over 7.5 pounds to go bang. I guess the Swiss don’t trust their soldiers with proper triggers. Is it bad enough to mess with accuracy? Likely. I could see better groups with a better trigger. However, the accuracy isn’t horrid. 

A two-inch group with cheap Russan ammo isn’t too bad. If I had paid over a grand for the gun, I would be disappointed, but I’m not complaining too hard. Two inches are admittedly the best groups, but they all stay under 3 inches or so. The longer sight radius and peep sight must help a ton, at least compared to a Kalashnikov. 

The recoil is mild and comfortable with minimal muzzle rise. The gun is plenty controllable, and that heavy Troy rail must help keep things under control. It most certainly doesn’t get hot when firing tons and tons of rounds. The gun keeps ticking and is fun to shoot. It’s smoother than AK and different enough than the AR series to make it enjoyable. 

Two position gas piston makes shooting it filthy easy (Travis Pike for TTAG)

The magazine release is an AK style design, and this is the same for standard 550 rifles. The placement is naturally ambidextrous, and you can do the classic Battlefield 4 AK speed reload. The gun also has a manual last round bolt hold open, but it only engages should the end-user manually utilize it. Even the LRBHO Yugo magazines won’t engage it. 

The SIG 556R is a rifle that makes it very easy to attach an optic too. You aren’t limited to red dots or weird side mounting fixed powers. You can toss on whatever optic you’d like, and best yet, you can get an actual cheek weld and use it naturally and with ease. 

Least the stock folds (Travis Pike for TTAG)

The SIG 556 rifles, in general, have become seemingly quite rare these days. It seems their owners are holding onto them, and I’m one of those owners. Because of a lack of spare parts, its not a rifle that sees a lot of action, or would be counted on as a primary combat rifle. It’s a dedicated safe queen these days, but she makes her way out to the range a few times a year. 

Are their better rifles? Oh yeah, but the real question you have to answer is, are there cooler rifles? 


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  1. I didn’t know they were obscure OR desirable. I sold mine as soon after it came back from SIG’s shop the THIRD time. After I had pretty much the same experience with a M400, I wrote off SIG rifles forever.

    • I had written off SIG forever after two bad purchases a couple of years after Cohen finished the Kimberization of Swiss Arms. My ears have pricked up a few more times since, and almost pulled the trigger on a 556, but held off just long enough to find out what absolute garbage they were from friends who fell for them. Between horrible quality control and contemptuous customer service during the worst of it, it is amazing they are still around.

      I understand that they are putting out some decent stuff now, but it hasn’t been long enough yet for me to trust them

      • Hear hear. I’ve got a few pre-Cohen Kimbers as well as Sigs (er, had, dang tragic boating accident,) and I wish I could get more like them. But I’ve tried the new stuff in both brands and they’re just not the same. Premium price tag for… basically the same out of the box reliability as some no-name Turkish guns I got for peanuts. I’ll take “tinker until it works” or “send it back to have it fixed” when the gun itself costs less than a case of its ammo, but when a gun goes for four figures that’s just unacceptable. Hopefully the next board of directors looking at hiring the guy has the sense to look at reputation rather than just last quarter’s sales numbers.

        • RBG and Nancy are swingers. Why settle for one when I’ve had both at the same time. RBG and Nancy don’t call me their “Golden boy” because I’m an up and coming young Democrat.

          Eric Swalwell 2020

  2. Saw some SIG rifles at a demo day lots of years back. Looked like an attempt to borrow features from FAL and AR without paying licence fees. We didn’t buy them and went with Steyr AUG (as featured in Running Man)

  3. A Steyr AUG is about as cool as a rifle can get if you want to show off your money at the range, and it actually works well to boot.

  4. The AR and AK platforms have been around forever, and will stay with us for decades to come. That says a lot.

    • They’re so prolific at this point that I can’t imagine a time when you won’t be able to find parts or ammo for them, barring some apocalyptic scenario where everything will become scarce.

  5. Seriously not an object of desire for me. Can see no advantage in having one of those when there are other models of semi-auto boomstick with superior reputations. Plenty at lower cost too.

    But, hey, if it entertains you, it is your money to spend!

  6. The Gen 2 version had most of the bugs worked out. Change the stock, fore end/rails to Troy, sights to Troy, upgrade the trigger to 4lbs + – ,and a few other small parts (krebs safety) and it is a smooth shooting low recoil rifle. The 7.62×39 drops like a rock at distance, but you can still get hits at 400m if you know your holds.

  7. I was really interested in the 556R when I first read about it’s announcement at Shot Show I believe, but then the reviews came in and were pretty mixed at best. I had a feeling they wouldn’t have long term support, and looks like that’s the case now.

  8. Yeah, the original Sig rifles were very poorly made… but the company has come a long way since then, particularly in the US. I really have to give them credit for pushing the boundaries of products in multiple directions.

    That said, would it be wrong to say that my obscure object of desire is a Keltec?

    • Which Keltec? I’ve always wondered about a RFB.
      (For other non-AR platforms, I’d consider a FN SCAR16 if I found it at a good price.)

      • Without highjacking the thread too much, for long guns Keltec’s SU-16 long stroke piston rifles is probably their best design ever. 2nd could be their shotguns. Every other long gun has a design choice that is a bit questionable, eg. pmr/cmr30 using unreliable feeding rimfile, rdb ejection mechanism across mag feed, etc. The SU-16 in 6mm arc would make a dope scout rifle…

        • Their ksg sucks. I’ve owned two and one day I’ll sit down and fix the one I still have so it runs right.

          It’s not the design, it’s the production value.

  9. Yeah been wanting many SIG rifles for a very long time. Given the cost though, I’ll just have to keep building my own. Whatever the manufacturer, you can probably build it for half what they are charging. Less you buy bulk.

  10. I have one of these. A few notes:
    1. The Hogue grip is fantastic. Huge improvement over the factory SAW-style grip.
    2. The MFI flip-up front sight is worth every penny. It retains the general aesthetic while letting you get it out of the way for optics use.
    3. The ADM AD-RECON-SL and AD-68-L are at a perfect height for co-witness. I run LPVOs on both my rifles, and this solution works perfectly.

  11. I can’t stand SIG. Wish TTAG would stop making SIG products a feature on the site…

    I once owned a Sig Mosquito (.22LR pistol) that had a measured trigger pull of 17 pounds, 3 ounces. I sent it back to Sig to fix this obvious defect, and they sent it straight back (after 6 weeks) saying it was “within factory specification.” If that is within their spec, I don’t want another Sig. If that isn’t within factory spec and they sent it back without remedy, I don’t want another Sig. I’ve had one Sig, and I’m done with them.

    • Not to nitpick, but the Mosquito/Firefly is made by GSG, not SIG. Judging SIG by that pile of crap is akin to judging Chevy by the Geo Metro. They literally only let GSG put SIG on it to avoid patent issues. I have a 227 with a 22 conversion, and despite being visually similar to the Mosquito they share no parts. Shoot a SIG in a centerfire caliber and you won’t have this problem.

  12. After my 2nd tour to Iraq I decided to get a ‘AR-type’ rifle but decided against traditional-ish gas impingement and the ‘reasonably priced’ piston guns that were CT compliant was a short list: SIG 556 SCM it is!
    I have to say, it’s been a great rifle. Many days in the great woods of Benning after; deer, hog, ‘yotes. Shot with an ACOG accurately out to 600 meters at steel E-types, could print puppy paws at 100 meters with Fed GMM 69gr SMK, put a folding stock on it from ACE…
    I’m not a man of many emotions, but considering that rifle has treated me well and has been 100% reliable… I *wouldn’t* be afraid to use the ‘L-word’ ‘bout her.

  13. I always see hate but the stock is ugly on the gen1 I have a gen 2 with Swiss stock and it is fantastic… I think they changed the barrel too there are melonite and chrome barreled versions mine shoot around 1 to 2 inches at 100 yards with Hornady steel cases… it’s the best you can do compared to a 553r without dropping 3 or 4K…

  14. KS-47, or as I nicknamed it the ARAK. PSA. It will pluck broken clays at 100 yds just fine. I will try farther out when it cools off and AZ is not on fire. One light primer strike was the only malfunction in 500 rds.

  15. Back in 2010 I was looking to buy a black rifle and the Sig 556’s caught my eye but with the administration at the time I was worried about bans and parts availability, so I bought a Colt.

    Over the years it kept multiplying in my safe, funny how that happens.
    Then late in 2019 Sig had an insane price on 516 uppers so I bought 2 and fell in love with the short stroke piston system.
    This started getting me to regret not getting a 550 when I had a chance so I started looking for 556’s on Gunbroker. I found a well used SWAT Patrol classic that runs like a champ, the only thing I don’t like is the short quad rail but it’s only for astetics.
    The more searching I did had me wanting a 556R and lucked out on what I think is a second generation 556R that saw minimal use.
    It’s as visually as the Swiss 55x rifles minus the AK magazines.
    I guess I lucked out because both rifles have been flawless.
    So 10 years later I have the rifles I originally wanted and now spare parts are even more scarce than before, but they are built like a tank, the only thing I’m worried about breaking is the firing pin and the spring for it and the extractor spring.
    It’s my last purchase, scouts honor.

    • I forgot to add, you can get a US made Swiss style stock on Gunbroker for $50, swapping them out is simple, there’s one pin on the hinge that just taps out and you’ll have to swap the latch which is one pin.


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