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What Happened to the Sig Sauer 556?

We take a look at the Sig Sauer 556, learn more about its origin, and ultimately answer the question...what happened to the 556?

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.

The Sig 556 Swat Patrol perfectly encapsulates that late 2000s tactical vibe.

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.

Sig’s first attempt at the 556. (Photo: 1911forums)

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.

Sig definitely went for the more classic styling here. (Photo: M4carbine.net)

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.

The Sig 551-A1 was as close to the original 550s as you could get. (Photo: Rifleshooter)

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 DMR with its heavy barrel. (Photo: Gunsamerica)

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.

Sig 556R (Photo: Gunmagwarehouse)

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.

Clearing the Sig 556R (Photo: Gunmagwarehouse)

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.

The Sig 556xi — shown here with the improved stock, pistol grip, and gas system. (Photo: TTAG)

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.

Sig 556 Swat Patrol with Aimpoint CompM2

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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18 Leave a Reply

  • Commenter Avatar

    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.

    January 26, 2023 10:24 pm
  • Commenter Avatar

    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.

    January 4, 2023 2:02 pm
  • Commenter Avatar

    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.

    December 31, 2022 7:10 am
  • Commenter Avatar
    Martin Riggs

    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.

    December 14, 2022 9:28 am
  • Commenter Avatar

    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.

    December 6, 2022 12:08 pm
  • Commenter Avatar

    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.

    December 3, 2022 1:25 pm
  • Commenter Avatar

    I got an early DMR, and it shoots great. Only wish it had a threaded barrel to accept a suppressor.

    November 3, 2022 3:37 pm
  • Commenter Avatar

    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

    October 30, 2022 8:26 pm
  • Commenter Avatar

    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.

    September 30, 2022 1:10 am
  • Commenter Avatar

    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".

    August 31, 2022 9:50 pm
  • Commenter Avatar
    Vader 5858

    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. :(

    August 18, 2022 4:15 pm
  • Commenter Avatar
    Larry Openshaw

    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.

    August 14, 2022 2:16 pm
  • Commenter Avatar

    "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.

    August 9, 2022 10:32 pm
  • Commenter Avatar

    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.

    August 9, 2022 7:14 am
  • Commenter Avatar
    Jose M.

    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.

    August 5, 2022 8:06 am
  • Commenter Avatar
    Bemused Berserker

    I wanted to get one when they first came out, buy after reading negative review after negative review, I changed my mind.

    July 31, 2022 4:12 pm
  • Commenter Avatar

    I like my 556R too. Still have it. I picked mine up 'slightly used' in a personal sale for $250.00.

    July 31, 2022 3:07 am
  • Commenter Avatar
    Daniel Hecht

    Love my 7.62 xI, wanted to get another but by that time they were stopped.

    July 30, 2022 2:35 pm
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