LWRC files lawsuit against SIG Sauer over SIG516 Rifle

LWRC Interational, manufacturer of AR-15 rifles for consumers and military, are suing SIG Sauer. LWRC claims SIG’s SIG516 line of piston-operated AR-15 rifles infringes upon their U.S. patent #7461581 “Self-cleaning gas operating system for a firearm”.

SIG516 Patrol Rifle

LWRC claims it is suffering irreparable damage and is asking the court for a preliminary injunction to prevent further infringement of their IP.

At least in the firearm industry, cases like these are almost always settled out of court. (more…)

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • charles222

    Gotta make money somehow when you’ve failed to secure a single government contract, I guess.

  • John Holland

    With so many gas piston AR products out there, I am so surprised that LWRC is filing Sig a lawsuit on the SIG516.

    H&K was one the first to produce a gas piston system for the AR platform. The whole point of a gas piston AR is that is would be more low maintenance than a direct inpignment system and therefore more reliable.

    If LWRC claim they own the patent to one part of the gaspiston idea. Does this mean that all the rest of the gaspiston AR manufacturers also risk to get a lawsuit from LWRC?

    I guess Ruger, H&K, Patriot Ordnance and others should be shaking their legs now….

    Or did SIG just screwed up here by not patenting all the parts on the SIG516 gas piston system? Which gave LWRC an oppertunity to file a lawsuit against it?

  • TCBA_Joe

    I can’t read the Scribd insert. What parts does it say Sig is infriniging upon? I know the originals were shown with LWRC bolt carriers. The piston setup itself doesn’t seem ripped off.

  • justin

    Hmm I just bought one of those…

  • Vitor

    The stupidity f IP laws and regulation. Only LWRC can claim a gas operated piston action is self cleaning? What is the actual novelty about the LWRC?

    Irreparable damage? So most people who bought a SIG rifle was only deciding between the SIG and a LWRC?

    What a joke that is.

  • I don’t understand why they’d be entitled to an injunction. Assuming that LWRC proves its case, money damages would seem to compensate them.

  • Some Guy

    I find it ironic that the patent is for a “self-cleaning” gas operating system, and that it is described as “self-regulating” in the patent, AND that the patent introduction derides the inclusion of a forward assist on the AR-15…

    …but the newest LWRC products ship with forward assists, have user-adjustable gas regulators, and their manuals recommend daily cleaning in the field…

    If Sig is stealing LWRC’s intellectual property by violating this patent, I would find it difficult to believe that it is causing “irreparable harm” to LWRC, for in addition to the above notations, LWRC has changed their design in numerous and substantial ways since filing that patent. LWRC has effectively acknowledged that the design they patented is unsuitable for real-world use…

    There is reference to another LWRC patent in the filing, but it seems incongruous with the rest of the filing, and I wonder if it was not part of another paragraph or section that was intended to be deleted. Who proof-read the filing?

  • Leo Atrox

    I think this is a bit of a stretch. I guess we’ll see …

  • Lance

    Not surprised a foreign company wouldn’t have that much insight into US guns and they bought some and used them for there design. go LWRC.

  • Gun snob

    So it’s just name infringement really

  • J.T.

    Really? I don’t see this going anywhere.

  • charliegibsonsucks

    US patent 7461581

    Why would Sig settle this out of court? So the Sig 550 was designed in the 70’s and enter production in 1986. With out knowing the exact operation of the SIG550 vs the SIG516, they will clam a deactivation of one of there own designs. I’m sure they have lots of prior art and product.

    my prediction..
    SIG will invalidate LWRC patent force them to go bankrupt.

  • Raymond

    I hate seeing these cases of fratricide among the quality firearms manufacturers of the world. It’s one thing when the dunderheads of A.R.M.S. sue the good people of LaRue, it’s another when both companies are building quality products

  • Erik

    LWRC can take a flying hike. That means that they “own” all gas piston systems going back to the early AR gas piston retrofit kits of the 60s and 70s.

    Which is bullshit.

    Screw LWRC, never buying any of their products ever again. And you know what they say about pissing people off? I’m telling 1000 people. Not 10. I think I’ll go buy another SIG tomorrow for shits and giggles. Sure they’re overpriced, but they, unlike LWRC, are worth it.

  • EzGoingKev

    I remember when pics of Sig’s rifle hit the net. Everyone asked if LWRC was making their bolt carriers as they looked exactly the same.

    Now I see this and wonder.

  • Nater

    HK didn’t make the first gas piston AR, Colt did. It’s an idea that has been around since the 1970s. That said, in terms of recent developments. LWRC and HK started making gas piston rifles at or around the same time.

    The Sig 516 is quite a bit different from the 550 series of rifles. The 550s series utilize a long stroke gas piston, not a short stroke.

  • G

    John Holland:

    It was actually Colt that made the first gas piston AR15:

  • Jason

    I didn’t read the document, but since the SIG516 was released, I have heard several times that the rear of the bolt carrier was the issue with LWRC. Apparently they appear to have…borrowed…that aspect of the design from LWRC.

    I have also heard that Adams Arms has an issue with an aspect of the Sig’s design as well.

  • Nater

    Furthermore, I don’t think this has a whole lot to do with the operating mechanism. The Sig 516’s bolt carrier group is literally a carbon copy of LWRC’s. Bolt carrier design is obviously very important in piston/op-rod AR-type rifles. Doing it wrong means you get carrier tilt. Did Sig rip them off? Probably. Was it illegal? I don’t know.

    If you crack open an M6A2 and a 516 and place them side by side, it’s fairly obvious that Sig “externalized a lot of their R&D”. I don’t blame LWRC in this at all. If Sig had ripped off HK, you know damn well that HK would sue.

    On another note, I own an M6A3 and a P226.

  • Vrt

    I say NO for US patent system!

  • Stella


    The Sig 55x system is completely different from the Sig 516.

  • arnie

    ” Not surprised a foreign company wouldn’t have that much insight into US guns and they bought some and used them for there design. go LWRC. ”

    I guess HK will be sued next……………That’s what’s wrong with this country, every one is trying to blame someone else for there troubles………..maybe the white house can send them some stimulus money…………

  • Nater

    As far as I know, LWRC isn’t doing too poorly. Considering the economic climate, pretty much every black rifle manufacturer is doing quite well.

    If this was some Chinese company and not Sig that was accused of stealing an American company’s IP…well no one would be blaming LWRC.

  • John Holland

    Haha, I didn’t knew that Colt had a gas piston prototype already way back in the seventies. It would crack me up if they also had patented the idea and that the patent is still valid today. Then Colt can sue every AR gas piston manufacturer!

  • Sleeper

    All of your speculation is wrong. Sig stole LWRCs one piece bolt carrier design and even used an LWRC bolt in one of their advertisements. It has nothing to do with the system, it is an actual part patented by LWRC that Sig is getting sued over. For all you sig fans I am sorry but sig USA is a horrible entity.

    LWRC has secured a contract for the DEA by the way. Haters gonna hate. LWRC and HK have opened a lot of eyes to the world of pistons. Now even Colt has developed a piston rifle. DIGS’s days are numbered.

  • Slimjim

    Before you guys bash LWRC. You need to realise that they completely stole the bolt carrier design blatently from LWRC instead of designing their own. Look at these two links below and decide if they have a case.

    http://i52.tinypic.com/2u636vc.jpg Sig bolt and carrier from the 516.
    http://i55.tinypic.com/nwkhmd.jpg LWRC bolt and carrier.

  • Nater

    Damn, you can’t even tell them apart. Ruger’s BCG is pretty close to LWRC’s, but you can tell them apart if you know where to look. I’ll say it again. If this was Norinco and not Sig doing this, no one would be whining about LWRC’s suit.

  • Jeff

    I’ve seen one of the early pictures with an LWRC bolt in it. Stupid on Sig’s part, but not conclusive proof that they stole LWRC’s design part and parcel. LWRC is not the only company that uses a one-piece bolt carrier for their piston rifles and having flutes at the end of of the carrier is not new either. Espcially if you are looking at helping the weapon drain more efficiently for “over-the-beach” testing. I’ll hold off on dropping an opinion either way.

    FWIW, I would love to have bought an M6, but it was just too far out of my price range. I’m curious how Sig is able to make a piston rifle with a free-float rail for so cheap.

  • Stella


    Wow. It really looks like Sig is using LWRC’s carrier. They are identical. That is pretty brazen by Sig; why did they not just license the part?

  • Nater

    I’m not curious as to why Sig can. They’re using economies of scale and likely scrimping here and there on materials. A better question is why HK cannot. Companies like POF and LWRC are fairly small, they can’t leverage massive production runs to bring down costs.

  • John Holland

    The LWRC patent describes in lenght about how their the piston system works.

    It does not go into detail about how the bolt carrier group works. There are not many different ways you can deviate in designing an AR bolt carrier. Even if you put a direct inpignment bolt carrier next to it, it will look very similar. Hence they all look alike and if you are producing an AR type rifle, probably the appearance of the gun will look alike.

  • haywood

    that pic you have of Sig’s bcg is the ones they first sent out with i think the first batch and then did a recall for the eawrly rifles without stating what exactly they were changing. Next you know all the new rifles are being sent out with an altered bcg…. look it up and you will see a dark gray bcg that has lost some of its material.

  • George

    LWRC has been complaining about this since last summer when the 516 first hit dealer shelves. I would guess that LWRC was asking for a LOT to make this problem ‘go away’, and SIG probably gagged at the idea.

    As for SIG Sauer not ‘understanding’ U.S. gun patents; before you start blaming the Germans or even the Swiss about this, you should be looking at New Hampshire first. Like way too much of their U.S. product lineup these days, the concept for the 516 (and the upcoming 716) originated here in the U.S. and is in fact made in Exeter, NH, not over in Europe. For that matter, the SIG Sauer 556 you see in gun shops across the land–a watered-down copy of the SIG original–is also made here as well. So if anyone did the illegal copying and patent infringement it’s likely the AMERICANS who run the show up there in New England who are the true guilty ones.

  • John M

    Have not looked at the sig up close for my self, but I will give some of you guys who are talking about quality my two cents. I researched for a year before buying my AR. I looked at POF, LWRC, ruger, the sig 556, NV, Daniel defense, ect. Literally every producer of AR’s. I finally picked LWRC. The quality is better than anything I have seen, and I’ll give it to POF they were my second pick. LWRC is the ONLY company that uses 7075 aluminium on every part, rail, everything, not even POF did that. Most of your major companies make good products and if your not in combat it really won’t matter much but I wanted the best I could get, and I got it. So, who cares about the lawsuit, but the quality of LWRC can not be questioned.

  • Bobby

    Well, how different do you really expect them to look?

  • BigDave

    Adams Arms who makes piston KITS has a beef with Sig too. Not sure about a second law suit however.

  • Mike Latoris

    These clowns lost as well they should have.