Sig is a huge company that does business worldwide. We are very used to Sig Sauer in the United States, but the Swiss branch of Sig is a little less known.
They produce a variety of weapons for the Swiss military, including the 550 series of rifles.
Americans being Americans means we don’t like when we can’t get things. For the longest time, getting a Sig 550 series rifle simply wasn’t possible — well, kind of. In 2007 Sig announced its intention to bring the 550 series to the American public in the form of the Sig 556 rifles.
Remember, this was only three years after the assault weapons ban when most semi-auto rifles on the market were the AR 15, the AK series, and Ruger Mini-14 and Mini-30. A new platform was a big deal.
Finally, Sig 550 Rifles in America!
Well…not really.
Sig released the first 556 to a rather lackluster appeal. The 556 might’ve been a 550 rifle on the inside, but it wasn’t on the outside. Sig attempted to AR-15ize the 556, and people weren’t stoked.
They took away the 550 furniture and replaced it with a non-folding M4 collapsible stock, and the rail system came as steel or polymer that looked nothing like the originals.
They accommodated AR-15 magazines rather than the unobtanium 550 series mags. However, a change that many didn’t mind was the new aluminum lowers.
People weren’t happy with the 556. Not only did they not look like the 550s, but they also had QC issues with canted rails and reliability issues.
Sig then created the Sig 556 Classic, which kept the AR-15 magazine compatibility but with a more classic 550 look. These weren’t truly authentic Sig 550 guns, but dropping the M4 stock and weird handguard in favor of Swiss military look-alikes brought back the distinctive styling of the original.
However, the stocks didn’t mesh well with the iron sights due to their higher position. The front sight got in the way while using optics, and you couldn’t change it. People still weren’t happy.
Will the Real 550 Please Stand Up.
Luckily Sig listened to the consumers, and we got the 551-A1. This new rifle gave 550 seekers a weapon as close as they could get to the real deal.
This included the 550-style furniture with a grey receiver set and authentic 550 mags that rocked into place. The 551-A1 answered the 550 fans’ requests, but many people were soured on Sig USA at this point, and the weapon flopped.
Then Sig did the Sig thing.
Sig is famous for releasing about a dozen different variants of their guns with minor changes. And while the 551-A1 gave fans the 550 they wanted, Sig didn’t seem to produce them for very long.
The Sig 556 became the main game in town. Following it was the precision-oriented Sig DMR, which featured a Magpul PRS stock, a match trigger, and a 21-inch barrel. We also got Sig 556 pistols with 10-inch barrels; sadly, this was in the dark times before pistol braces existed.
We also got the Patrol rifle with a shorter handguard, the SWAT rifle with a Picatinny handguard, and even a SWAT Patrol version with a shorter Picatinny rail.
During this time, Sig produced my favorite 556 variant — the 556R. The R stands for Russian, as it accommodated the 7.62x39mm round and AK-47 series magazines.
Saly, the 556R had immediate issues upon launch. The Gen 1s sucked, and as an owner of the Gen 1, mine was super unreliable with numerous failures to eject. Luckily Sig fixed mine, but they eventually released an improved Gen 2 model to address the problems.
They also released various models like the 556R Hunter, a Sport Configuration Model for ban states, and even offered a 556 Holo that came standard with a red dot sight.
However, the fumbled release of the 556R was considered a major failure, further tarnishing the reputation of the 556 line.
Enter the 556 XI Series
Sig decided to modernize the 556 series with the XI series. They went full bore, adding a new stock with a cheek riser for better sight acquisition, a three-position adjustable gas system instead of two, and an M-LOK rail system to top it off. It was offered in 5.56x45mm and 7.62x39mm, with a .300 Blackout version planned to be released.
They enhanced the ergonomics by making the charging handle reversible for left or right-handed use and featured full ambidextrous controls. Yet, it still suffered from a poor trigger, small aftermarket, and lackluster accuracy compared to the AR-15.
Final Thoughts
As a bit of a contrarian, I’ve always liked AR alternatives; thus, I’m a big fan of the 55X series. I love my 556R and find it to be all sorts of cool.
However, the Sig 556 suffered poor sales. The rifles were expensive too, and the unreliability of specific models tarnished their reputation. They also didn’t offer any significant advantages over the AR platform and had worse accuracy and downright sub-par triggers.
Sig discontinued the series and seemingly replaced it with their AR variants and their MCX rifle. The 556 now exists as a distant memory in the minds of rifle owners.
Does anyone in the audience have any experience with the Sig 556 series? If so, share it below. Still looking for something different than the AR-15? Check out our article on the best 5.56 rifles that are not AR-15s.
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I back in the day looked at the 550 version. And passed to much colt like. Later I ended up with the Xi series in 556. Looked good but with use quickly found issues. The rear sight was not usable with out the riser on the stock. Made a cowitness optic difficult. You had to remove the sights get new ones and ditch the cheek rest. The rail was to short for the long barrel. Trying to make a 553 look alike with a 16 inch barrel. No go accuracy was inconsistent. Had they put a long rail handguard , a 550 gas piston, on a 16' barrel without the cheek riser sights problem it would have been great.
But sig continously drops supporting products leaving you holding broken stuff. Mcx versions 1 thru virtus few parts compatability. Various changes and fixes ok teething changes for developmental problems. But having a bolt assist assembly that falls out of the gun ? No leaves a big opening leaving garbage to gum up the action. Cheap Chinese bolts holding stocks and sights on or rather floor when breaks. A 553 or 552 yes anyday just not a Franken gun. Same as the cheap parts in 320 series. Mim and out of speck parts nope will keep my p226's . With the action work done its perfectly capable. Base government model without work its horrible having to break in stiff. Sig has dropped 40/357 caliber bad idea 357 worked well and was accurate. 9mm well good fuel in good results, cheapest and poor outcomes.
I'm late to the comments here... I was looking for 556 stuff online and tripped across this article.
I have (3) SIG 556 Classics, and am always watching for another. Mine function flawlessly and, using match grade (69 - 77 gr. Black Hills SMK) ammo and a decent scope, will hold about 1.5 MOA, which is fine for a combat carbine.
Have 556 Classic SWAT...first one would not group to save its life. Sent back to Sig with their lifetime warranty...they could not figure out what was wrong either so they replaced it with one of the final 556 Classic SWAT off the production line as the new 556xi was being released. This one has been great. Usually keep a LPVO scope on it from Vortex but took out last year for some predation whitetail hunts with a farmer and a nv scope mounted on it....worked great.
Have the 556 swat, 556 pistol and the 556-22 love all 3 of them, one small problem with the 552-22 and asked Sig if they would send a part that was not quite right. They said no and said send to us and we will replace it. Had to pay shipping to them, but they returned it quickly and credit my shipping cost. Very happy with all 3 and Sig. My grand kids love the 556-22 and that is all they want to shoot. Mind you I start them on 22 lr bolt and not until they become proficient with the bolt and fire arm safety rules become second nature to them do they get to move to semi auto. Sadly I only have one and all 12 want it left to them. Maybe I should put in my will who gets the 556-22 on which month. Except the one that gets Feburay will feel shorted! If I could find 11 more would snatch them up as fast as could find them.
I had a 556xi (556/223) for several years and sold it. I got tired of sending it to sig for repair. I honestly don't miss it. I pretty much forgot about it when I got a galil ace anyway. Since I wanted an AR-15 I got a sig m400 and it's a reliable and fun shooting rifle. Sad to think about when I had a p226, (2) p229s, 320, 365 over the years as well. While I sold the 226 and 320, I am never getting rid of my p365 or 229s.
i will keep my scar-17 as it a fn fal totaly improved. + my romaine under folder akm as it only needs a dust cover with a scope base and a better trigger
Texas Gun Trader had a NIB 556 Swat for sale as we speak. I own a Swat, DMR and a Russian. All function great but the DMRs plastic dust cover disintegrated and the but pad on the Swat is disintegrating. Sig didn't have any interest in addressing the issues in spite of the "life time" warranty.
You forgot to mention the 556 SWAT SBR. Its everything that you'd expect from SIG.
The FN FAL is probably my all time favorite firearm and the AR-15 is pretty damn good too aka these neat little ‘Sig 556’ rifles almost seem like the FN Scar in that they also combined the best aspects of European and American modern rifle design/mixing FAL and AR qualities.
I never got to fire a Sig 556 but handled both the 556 and 762x39 R models in stores and absolutely loved the 556R (Russian as in 7.62x39 takes Aak nags) one and could kick myself for not buying one with the folding stock back in the day just for the cool factor alone. That gun was like something out of a decent Hollywood action movie and was bad ass looking like the real Sig 550 & 551s from Europe and looked built extremely well to boot!
Sig Sauer Inc. -if you ever do read this please do consider an FAL or AK style gas piston simple reliable model but with the ergos of the FAL charging handle and easy gas piston cleaning/removal and the ARs perks (execellent precise iron carry handle sights that are detachable with a flat top easy to mount optics, great ambi controls, easy pivot pin takedown for cleaning, no frills simple to fix and adjust triggers to light pulls A3 lower, etc) once again and make it in 762x 39 and 51 (that Thick 30 cal AK and 308).
All the best. Thanks for reading and keep the 2A going guys and gals!
I have two of them, an SBR and DMR. Both run fine and are super accurate. Triggers are amazing. The SBR began life as the 'pistol' and was legally converted. After a few thousand rounds the back plate (U-shaped buffer plate pressed into the back of the frame) came loose, but these can be repaired if you are good at gunsmithing, as Sig does not repair them. The DMR can hit running armadillos at 200-300 yards from a tripod with a thermal. Both are heavy as are all Sig rifles, and gassy when suppressed. I think the early variants were very problematic, and hence the line was doomed. Your loss if you did not get one of the later ones with the enhancements as they are amazing and incredibly accurate. I will never sell either of mine.
I’ve had a 556 Classic for about ten years. It’s a superb rifle. Mine has the Magpul CRT stock. Accuracy is as good as any of my ARs. I mounted the small SIG STS-081 red dot sight. It’s a great combo. I have many other ARs and none of them is any better than the 556 in either reliability or accuracy. The only thing I’d change (if I could find the parts at an affordable price) would be to swap the CRT stock set up for the original Swiss pattern.
I have a Sig556 purchased in January 2009. Mine has functioned flawlessly with all brands of commercial 5.56 ammo and the reloads that I produce. It came with a small crappy red dot that I tossed in a drawer and replaced with a decent scope. It's accurate enough for the target shooting I do. I also own a traditional AR (S&W M&P 15) and if I could only keep one rifle that uses AR mags I'd keep the Sig556.
I have 566r that I bought new about 10 years ago with a folding stock and also came with a SigTac STS red dot. The rifle has functioned perfectly and is amazingly accurate. People at the range always want to check it out and shoot it. I will never part with it.
I have one of the early ones. It has the weird hand guard but came with a folding stock. With less than 10 rounds through it the bolt jammed. A cross pin in the bolt had backed out. I sent it to Sig and they repaired it. They told me the parts were out of spec. Was rather shocked at getting that level quality from Sig.
Purchased a NIB 556 swat patrol some years ago. Loved it except for the grip angle. Replaced the stock grip with a Hogue overmolded pistol grip w/o finger groves. Also did not care for the sights. Removed both the front and back sights and mounted a red dot sight and flip up - co witness front and back sights. Also have a quick detach, flip to the side 3x magnifier. Very accurate. Have no problems nailing targets at 200 yards. Really like the fact that it is piston driven and not direct impingement. I do have several ARs but prefer my Sig 556.
Do you have a stock on it? If so, what kind? I’m starting the SBR process for the first time and I haven’t found a stock I love for my current SWAT Pistol. Thanks!
Have both the Sig 556 Swat Rifle and Pistol. Both run with no issues what so ever. Both run great. Liked them so well when Sig intorduced the Sig 522 in Swat I snapped it right up. Only thing I do not like is the long take up on the trigger. Would love to replace them but can not find any company that makes one to drop in. Everyone that I let shoot any of them loves them just like I do. I really like the side charger on all 3. But that is just me and Martin if not others.
I worked at a small PD in northern California years ago. The sig 556 was our issued rifle. One of the best features thats not often talked about was the removable charging handle. Simply remove it on an empty chamber and the gun is mechanically inert. Great for LE use.
I have a 556 classic that I absolutely love. Ran thousands of rounds through it. No problems. reliable, accurate. It's a shame they discontinued this rifle.
I have a 556 Swat Patrol, I think it was the last of the series. It's unfortunate that you can't get parts. It is a wonderful conversation piece.
I got an early DMR, and it shoots great. Only wish it had a threaded barrel to accept a suppressor.
I have a 556xi russian only have maybe 200rds thru it but it ran flawless . I don't recall measuring groups but it did not shoot bad at all with wolf steel case. It is for sale
I had a Swiss made SIG Exeter NH imported 552 in my possession for a while and it was certainly my favorite 5.56 . I always hoped SIG Newington was going to be able to pull it together and reproduce the magic and during my short time there I did some work on the receivers but management was more focused on the MPX . Obviously the ARs they where producing at that time did not take up much R&D resources.
My second favorite non-AR 5.56 is the Czechpoint VZ-58.
I have a 556 classic and love it. Truly is the best of both worlds AR and AK. Runs like a fine swiss watch and always impresses anyone who witnesses it in action. Would trust it like an AK to handle anything in any conditions. If the SHTF its getting grabbed. However, like Vadar 5858, " With no support from SIG on the 556 line. The rifle is relegated to special occasions and bragging rights".
I have both 556R gen 2 and an early model 556 (full of swiss parts).
Both are great rifles, but not my "go to" despite desperately wanting to.
I shoot often enough that all my firearms are well used. With no support from SIG on the 556 line. The rifles are relegated to special occasions and bragging rights. :(
I bought my 556 in March of 2009. I still have it and it shoots great! Never any problems a solid and great shooting firearm.
"the Swiss branch of Sig is a little less known" - A true shame . The "SIG" in "SIG Sauer" stands for "Schweizerische Industrie Gesellschaft", which translates to "Swiss Industrial Society". Without SIG, there wouldn't have been the "SIG Sauer" existing today. People tend to forget where the true roots of their firearms lie.
They're super expensive on Gun Broker - especially the XI's, so people def want them. An unfired XI Russian recently sold for $2800.
I have XIs in both the 5.56 and the Russian. I dolled up the 5.56 with an ACR stock and Krebs safety lever. I get sub MOA accuracy with Hornady Frontier 55 and 75 gr. It's my favorite rifle among many. Not sure if I want to shoot the unfired Russian or preserve it.
I have a Swat Patrol version and a XI Pistol version that has the biggest Sig brace. They are unique. When people ask what is that, I’ll explain it is when an AK and an AR had a one night stand. Unfortunately Nobody wants them.
I wanted to get one when they first came out, buy after reading negative review after negative review, I changed my mind.
I like my 556R too. Still have it. I picked mine up 'slightly used' in a personal sale for $250.00.
Love my 7.62 xI, wanted to get another but by that time they were stopped.