Breaking: Leitner-Wise Files Suit Against LWRC and Sig Sauer

Earlier today Paul Leitner-Wise of Leitner-Wise Manufacturing filed a lawsuit for patent infringement against LWRC and Sig Sauer. If you are unfamiliar with Mr. Leitner-Wise you may be familiar with the company he founded, LWRC or Leitner-Wise Rifle Company. Mr. Leitner-Wise is the patent holder for the self-cleaning gas operating system that LWRC currently uses on their piston driven rifles.


Mr. Leitner-Wise sold LWRC in 2005 and remained an employee of the company, in 2006 Leitner-Wise left the employ of LWRC. Part of the employment contract as outlined in the relevant facts section of the suit is Mr. Leitner-Wise was to be paid a 0.5% royalty from the net sale of every rifle that used his piston system. The suit goes on to state that the contract was removed from his possession at some time around when Leitner-Wise’s employment ceased.


The lawsuit also goes on to name Sig Sauer as a defendant, claiming they are using Leitner-Wise’s design in the Sig 516 rifle without paying proper royalties. The suit then goes on to request that Sig pay according to the same royalty agreement that LWRC aggreed to when Leitner-Wise signed on as an employee. Over a dozen other rifle designs were named in the suit as using the patent, some of the more notable ones being the Sig MCX, the Sig 516 and the Sig 716.

You can read the entire lawsuit by clicking here.

As always expect us to update you as we learn more about the status of the lawsuit.

Patrick R

Patrick is a Senior Writer for The Firearm Blog and TFBTV Host. He likes guns and has liked shooting guns for as long as he can remember. You can follow Patrick on Instagram @tfbpatrick, Facebook, or contact him by email at

The above post is my opinion and does not reflect the views of any company or organization.


  • Harry’s Holsters

    Why wait so long to file against LWRC if they violated the agreement? Was there 10 years of mediation?

    • Patrick R. – Staff Writer

      Great question. I am sure that there will be some entertaining and interesting developments as the process unfolds.

    • allannon

      This seems to be common in patent suits, and I generally don’t understand why.

      Sometimes it’s a “submarine suit”, where a patent is left lurking until it’s most profitable. But since he’s a former employee, and LWRC was well aware of the patent, it doesn’t seem likely in this case.

      Maybe some back-and-forth between LWRC and Leitner-Wise’ lawyers?

      • smartacus

        maybe the back-and-forth between lawyers was deliberately slow to let it ripen

        • KestrelBike

          Haha I like the way you think.

        • Harry’s Holsters

          Billable hours never hurt an attorney!

    • smartacus

      i’d have to agree the wait was probably to let the fish grow bigger first.

    • Joseph Goins

      He probably needs the money now that the UK has left the EU.

      • Harry’s Holsters

        You don’t leave that amount of money out there for so long. I’m guessing there is more to the story.

      • CavScout

        Don’t be an idiot. Can’t wait for the UK to leave the EU in the dust. You know, once they ACTUALLY leave the EU, if they really end up leaving it. But if the EU is as anti-gun as the UN, then I hope it FAILS.

  • Vitor Roma

    More patent trolling. Just wish patents would last 5 years instead of 20. C’mon, it’s a almost century old short-stroke gas piston that I’m sure Leitner-Wise payed nobody to copy and do some little modification that changes very little the overall mechanism.

    • Austin


    • Joseph Goins

      The company needs to pay for the modification he created that enabled the company to make money.

  • Going to be interesting to watch. I was under the impression that the 516, MCX, and other SIG piston rifles are derived from the 550 series which was designed in the 1970s.

    • Austin

      That would be the Sig 556 and it’s derivatives

      • dshield55

        The 550 series didn’t start with the 556.

        • Austin

          But it’s the base model of it in the US market

    • JSmath

      All the variations of piston AR’s aren’t that much different, in the grand scheme of things, but the 550 series is distinctly different from the AR15-with-short-stroke-piston design that would apply to the 516. Just google the models and look at their bolts carriers. I think that’s the distinction this patent is trying to make a claim on.

    • Anonymoose

      The 54x and 55x are long-stroke pistons, where the piston is attached to the bolt carrier group all the way through cycling. They’re basically like an AK action inside an AR15-style 2-piece receiver. The HK416 and 417, SIG516 and 716 and MPX/MCX, OA-93, LR-300, LWRC, Adams Arms, POF, Ruger, Colt (LE6940P), Larue, LMT, SCAR, ACR, and almost every other piston-driven AR15 derivative and “replacement,” with the exception the PWS rifles and Robinson XCR, are all short-stroke pistons, where the piston just shoves on the bolt carrier before springing back while the carrier finishes cycling independently.

      • Sam

        Mmmm… PWS. I have a Mk116. I tell anyone thinking about getting an AR, especially a piston, to get a PWS.

  • gunsandrockets

    self cleaning?

    • Austin

      It also mops you safe

    • Patrick R. – Staff Writer

      Hey man, I just type the words that they use to describe things. I have a feeling it is about as self cleaning as the Colt 601 M16s were.

    • Zachary marrs

      Lots of firearms have some form of “self cleaning”

      That doesn’t mean that the gun will clean itself spotless, however

    • More like “self scraping”. You know, like about a zillion other gas piston designs have been since gentlemen wore hats and detachable shirt collars every day.

  • dshield55

    He claims the contract wasn’t in his possession. I suppose that’s to justify why he waited 10 years, but it doesn’t make sense that he couldn’t have asked his old company for a copy so I’m betting he loses on this.

    • Exactly . What, did the company send a black bag team to his house to break in and steal the contract, assuming he was too stupid to have heard of the word “photocopy”?

  • JSmath

    I don’t see the SIG design having that much similarity to the patent specifics. Haven’t gotten in up realclose look to determine if the piston uses the same approach to valving the gas, but it could be the retrofitted AR15 piston-carrier design that he’s going after.

  • Looking at the patent in question, it looks like he just patented the AR-18/AR-18 gas system stuck on a AR15. I’m not sure how this would stand up to scrutiny as it seems like a fairly obvious invention. Maybe I’m missing something.

    • Austin

      Yeah this suit just seems like a good way to loose whatever money you got as part of the original deal.

    • tazman66gt

      Kinda like the drop in trigger suit that Mossberg/CMC is pressing.

    • randomswede

      Unless there’s some subtle but crucial detail I’m absolutely with you, it should never have been awarded. It’s just a step above getting a patent on a mirrored paperclip.

      However if he has the patent anyone who wants to sell something that the patent describes, lawfully has to make a deal with the patent holder.

    • abecido

      And the AR-180 gas system is very similar to that of the SVT-40

  • I wonder if PLW’s sockpuppetry on ARFCOM won’t come up. As I remember it, it was his impersonation of an active duty SOCOM officer that led to his termination from LWRC.

  • Austin

    That site seems questionable at first glance

    • kyphe

      amateur site certainly but he must definitely motivated someone enough to go to the trouble of making it. The last page deals with the current law suit. It gives details which I should be able to independently verify if true

  • Paul Reavis

    Sometimes you let the offending party keep making money on the patent so that they can be sued for treble damages for knowingly violating it. He can be awarded 3 times the royalty going back to when they stopped paying that way.

  • Scooter

    What kind of moron doesn’t have a copy of a legal document that important in a safety deposit box somewhere offsite?

  • This sounds less “frivolous” and more “fraudulent”.