springfield hellcat sig sauer P365
Neither of these popular pistols are on the California handgun roster. But they're for sale in the other 49 states. (Jeremy S. for TTAG)

SIG Sauer announced today they are suing Springfield Armory alleging patent infringement on the P365 magazine design. I remembered the announcement of the new P365 like it was yesterday and was left wondering how the hell they managed to fit ten rounds in such a small gun. Well, the answer was a unique magazine design.

Springfield’s popular  Hellcat is a similar-sized pistol designed with the same goal in mind as the P365. They shoved as much ammo as they could into a remarkably tiny package. In fact Springfield got one more round in their standard flush magazine than SIG did

Magazine design went a long way in achieving this feat. According to SIG, Springfield’s Hellcat infringes on their patent of the P365 magazine.

Here’s SIG Sauer’s press release . . .

SIG SAUER, Inc. Files P365 Magazine Patent Infringement Case Against Springfield, Inc.

NEWINGTON, N.H., (May 11, 2021) – Today, SIG SAUER, Inc., filed a lawsuit in the United States District Court for the Central District of Illinois, Rock Island Division, alleging that Springfield, Inc. (Springfield Armory) infringes two SIG patents relating to SIG’s P365 magazine.

The P365 has seen tremendous commercial success due to the innovative design of the high-capacity magazine. In its complaint, SIG alleges that Springfield Armory’s making and selling of certain “Hellcat” branded magazines infringes upon two SIG patents. SIG SAUER is seeking injunctive relief, as well as monetary damages for Springfield Armory’s past and ongoing infringement.

Ron Cohen, President, and Chief Executive Officer, made the following statement:

“When the SIG SAUER P365 was introduced, it took the market by storm as the most innovative high-capacity, micro-compact pistol to be introduced due to its magazine capacity, and quickly became one of the top-selling handguns in the market due to this unprecedented innovation. SIG is not a litigious company, but given the extent of infringement by Springfield, SIG has a responsibility to protect both our intellectual property and the significant investment we make to develop our innovative products. As a company, we are proud to yield more than 100 patents worldwide, with more than 40 patent applications currently pending, and we will protect the extensive research and design that goes into developing these patents rigorously.”

Patent Infringement?

The SIG P365 magazine functions as a combination of a double and a single stack design. The bottom portion is a double stack, and it gradually slopes into a single stack. This allows them to squeeze ten rounds in a short little magazine. The P365 magazine patent describes it as such.

A detachable box magazine for firearms includes a hollow magazine tube extending longitudinally along a median plane. The magazine tube defines a single-stack portion extending to an upper tube end with an upper tube opening. The magazine tube defines a double-stack portion positioned below the single-stack portion and extending to a bottom tube end with a bottom tube opening. For example, front portions of the opposite tube sidewalls have a stepped shape between the upper tube end and the double-stack portion, and the rear portions of the sidewalls have a linear taper between the upper tube end and the double-stack portion.

The Hellcat has been around for almost two years now, so why is SIG only now suing Springfield? It seems the patent wasn’t granted to SIG until March 30 of 2021.

I’m no legal beagle, and outside of my knowledge of bird law, I’m lost on most subjects involving intellectual property and patent infringement.

Does SIG Sauer have a case here? They no doubt believe they do, but that will be up to a court to decide. Stay tuned.

70 COMMENTS

    • Idiot Justices let Google get away with blatant IP theft from Oracle and this set a terrible precedent for future R&D. It will be interesting to see the outcome of this case.

      • Google, and Oracle?! Thundering Jayzus! Any of you young fellers ever hear of a cat named Bill Gates, or a wanna be hippy named Steve Jobs? They’ll show you how to do patent infringement and IP theft and get away with it. They were doing it back in the 80’s.

    • Maybe, Just looking at an old S&W Shield mag (not the plus) and it goes from a simi-double stack to single stack. So they could lose on this just being an obvious next step, but who knows. I wouldn’t trade my little XL for anything Springfield makes.

      • Amen! Love my P365. SIG hit the nail on the head. There’s nothing in Springfield’s catalog I would buy from them.

    • “Yes. Sig has a case. “First to file” changed the world, and continues to do so.”

      Only if they can prove a geometry unique to their patent.

      The case collapses the moment a prior design is found that mimics what Sig is claiming, no?

      • IF such a prior art magazine is found, then the patent claim(s) covering such earlier magazine would be held invalid. For both patents (presumably US 10480880 and 10962315) there are geometry limitations that are presumptively novel and unobvious.

    • The patent also can’t be for something obvious which this magazine arrangment certainly is. As to a 5th grader.

  1. What you describe as a double to single stack is far older than SIG’s patent claim, it amazing what you find when you read old books and magazines.

    • Exactly. If I recall correctly, the doublestack version of the Makarov tapered down to a single stack at the top of the magazine- a necessary step because the grip was widened to accept a double column magazine, but the rest of the gun was unchanged from the original single stack design.

    • “What you describe as a double to single stack is far older than SIG’s patent claim,…”

      A true ‘double-stack’, or a quasi double-stack?

      Looking at handgun magazines I have on hand, they are all of a ‘staggered’ double-stack variety that taper to a single-stack at the top…

    • Looking at the file history of US 10480880 (app. no. 16/230028), the original claim was just for the double stack transitioning to single stack, but they had to add additional language on the magazine geometry to get allowable claims.

  2. Hmm. Wonder if they will also go after the Sheld Arms mags for the Glock 43X? That mag rxpands the G43X flush mag capacity from 10 to 15 rounds.

    • sig offers a 15 rd mag for the P365 as well. I have a P365 and the 10 and 15 rd mags. 15+1 is a good feeling these days

  3. Sig has a claim. First to file. However, the patent can be invalidated if Springfield can show prior art (by anyone) prior to the filing.

    By filing (and being granted) the patent, the patent is presumptive good. The burden lies on the infringer to show that the patent is invalid. The patent office itself does not really do any due diligence to see if something already exists.

    • sure they can, the Kel-Tec P11 mag is 10 rounds same size & geometry as sig’s “invention” and also 12 rounds in same package, so it really was better AND you can put the Kel-Tec P11 mag into the P365 although it won’t latch, but that shows you how much they are the same.

      • This. The only “innovative” thing about the P365 is that it takes the p-11 mag and puts it in a good pistol. They never should have been granted a patent, and suing someone for copying a decades old Kel-Tec design is ridiculous.

      • Kel-Tec did it way back in 1995. That said, is there something different about the geometry of the Kel-Tec.and Sig magazines?

        Speaking of infringement, the Ruger LCP is pretty darn similar to the P3AT (I own both).

      • Keltec copied the Smith & Wesson model 59 series mag design for the P11. So much so the Smith mags fit and function in the P11.

  4. Since sig is the darling of the military now…..Who do you think will come out on top?
    I’m not saying who’s right or wrong but when you have an “IN” to the Govt. you can never be wrong……Like a liberal!

    • So you think the US Patent office and the US Federal Court system will care that Sig has a contract for a different product for a completely different branch of “government”?

      • I’m thinking that’s exactly what he was saying!
        They may care until someone has a little “talk” to them.

    • Springfield betrayed America; so if you’re an actual patriot like you claim you should be rooting against them for destroying most of the local gun stores in Illinois.

      • Fake news. They didn’t propose the bill, they just sought their own personal carve out. Be mad if you want but the only thing they’re guilty of is trying to buy their way out of a bill the anti gunners were going to pass regardless. The talking point is old and duplicitous, give it up.

  5. While I much prefer SIG’s trigger, Kel-Tec managed to build a hi-cap pocket pistol using the reliable, widely available, and more space-efficient conventional Smith and Wesson magazines 20+ years earlier.

    • Exactly! Everybody went gaga for the P-365 like it was the first gun to ever be that size/capacity when the Keltec P11 was something like 25 years old already and had almost the same dimensions (as do the SCCY clones). SIG’s double to single column magazine was a solution in search of a problem.

      I guess first gun “by a respected manufacturer” to be this size/capacity didn’t have the same cachet as simply ignoring that the technology was already out there a long time and pretending to be first.

      • I think the mag was a “solution” in search of a patent.

        SIG had created a pistol that was a synthesis of sensible pre-existing features with no actual new innovations; knew it would be a hit, and tried their best to lock in the niche as long as they could.

    • Kel-Tec doesn’t use “two into one” mags, and (other than size, and the same modified-Browning locking that most other pistols use) there aren’t many similarities between the hammer-fired DAO P-11 and the striker-fired SA P-365.

      • we are talking about the mag itself, the suit isn’t about the pistol design.
        The Kel-Tec P11 10 round fits into the P365 as does the 12 round, geometry is the same. They just need to show that to the Court and SIG ought to lose big time, they didn’t design anything, they copied an existing MAG design

        • I know what we are talking about (read my first line).

          The P-11 takes S&W 59-series (conventional straight tapered) magazines, although Kel-Tec made its own shorter mags for greater compactness.

        • Have you measured all the slope angles, corner radius, and follower design as being identical?

          If not, then I don’t see how you can back up your premise.

  6. If this is allowed, then both Kel-tec and SCCY should file against Sig. Kel-tec had the first truly compact 10 rd double stack mags. And the SCCY was also nearly identical. Kel-tec had their mag out 20 years before Sig.
    This is ridiculous!

    • I totally agree with you on Kel-Tec, the P11 mag was a truly compact double-stack 10 rounds when it first came out, then when the Federal ban was lifted that limited mags to 10 rounds, the same exact mag package went to 12 rounds by Kel-Tec changing out the spring, because it was originally designed for 12 rounds, but had to be held back to allow only 10 rounds because of the Federal mag ban that went into effect right before Kel-Tec was set to release it. SIG to this day can’t even do that, they have to extend the mag beyond the butt of the pistol to add 2 more rounds.

  7. Llama had a 2-into-1 stack magazine in the Omni in 1980. Sig should be ashamed of themselves for pretending they invented it.

    • Par for the course. There’s so much hate for Springfield but IMO Sig is far scummier in product quality and business practices.

  8. Thirty or so years ago I had a couple of aftermarket 16 round magazines for a Beretta 92 compact that I modified to work in a Taurus compact. They had a ” clock spring” that ran down the back interior wall of the mag and coiled up under the follower. I can’t for the life of me remember the brand, but it was a very clever way to increase capacity by 3 rounds in the same physical size magazine body. I think the company disappeared when the AWB took effect.

    • It was Ram-line and they were JUNK. I threw
      mine in the trash years ago. The coiled leaf spring design is still used in some 10/22 25rd magazines today.

  9. Nearly all pistol magazines are double stack single feed even the old 1907 Savage pistol. The old HK p7M13 has a long single stack portion compared to most double stack magazines but it’s still a double stack single feed. Some sub guns like the STEN and M3 from WWII were single feed double stack although double stack double feed like the Thompson, Uzi, Mp40 & Mp5 are easier to load. I can’t believe they were issued a patent on a design so common in use. Then again Glock got a patent on the trigger blade “safety” they copied from a 80 year old Iver Johnson safety hammerless revolver. Go figure.

      • Ohhh, a shot too late! One that I know of is Mark Finnie’s 2013(?) -ish patent on a “Multi-spoke Bifurcated Motorcycle Wheel”, and that to be resubmitted a number of times before a patent was granted, so there must have been others previously patented. Maybe try patenting something easy, like Oxygen.

  10. There are only so many ways to make a magazine…. it’s a tube with a spring and a follower. Sure, you can make the tube out of metal or plastic, add rails to the tube, or use a flat spring vs a round spring, but ultimately they will be blatantly similar to each other.

    • Agreed. The fact that Springfield managed to fit another cartridge in argues for them, I believe. Personally, I think most judges will be clueless here.

  11. I personally doubt that SIG customers consider Springfield Armory and vice versa very much. That’s not a slam on either company.

    • I own both Springfield Armory and Sig guns. In fact, I own a 365 and a Hellcat. I know a number of other folks that buy both brands.

      • I think a lot of people consider both the P365 and the Hellcat (and now the new double stack Shield, and Ruger too).

        There is probably a lot less overlap of P365 and P11 owners (plus the P11 is now discontinued).

  12. It’s a box with a spring in it. There’s nothing magical about Sig’s design and I’ll bet this lawsuit has more to do with preventing aftermarket magazines from being sold than anything else. It’s a super popular pistol and spare mags run for $50 each, so I’m sure Sig would very much like to keep that gravy train running.

    But from a broader standpoint, I’m not even sure who to root for here; it’s like watching a Nazi beat up a Klansman. On one side, we have a company who pulled some blatant crony capitalism, anti gun bullshit in Illinois, but on the other hand we have a company who knowingly sold an ostensibly defensive handgun that would fire itself if you looked at the slide wrong. They’re both scum

    • Bribing (excuse me, LOBBYING) a representative to get an exemption for your company isn’t anti-gun. They had no hope of scuttling the anti-gun bill so their lobbyist decided to look out for his clients. It’s slimy but it’s standard business practice. I’ve owned a few springfield pistols and they’ve been fine, but there’s been a lot of hate for them (for no apparent reason) since long before the lobbying incident.

      Sig America on the other hand enjoys ducking their customers good and hard, has had numerous issues and generally has made crap rifles.. besides being big into proprietary nonsense and charging ridiculous prices for their magazines.

  13. Even beyond just being single feed, M&P Shield magazines definitely have at least one cartridge in them that’s completely, unambiguously, single stack on top of a body that’s (barely) double stack. Springfield is garbage, but this is definitely prior art.

  14. The SIG fanboyism turned me off of the P365 back when they first were announced.

    That douchenozzle shill over at soldiersystems.net got a free factory tour and shooting session and was totally sucking SIG’s cock in his writeup, even though the gun choked in the freezing cold at the range.

    When someone posted that his SIG slideshow full of “first” and “only” pronouncements ignored the 20 year old Keltec, and that their “innovative” magazine wasn’t necessary to fit 10 rounds in that size gun he got super defensive. Not SIG’s fault, but that shitty excuse for journalism left a bad taste in my mouth about the gun.

  15. The Smith & Wesson Shield Plus magazines also have a very defined single-stack portion atop the double-stack column. I guess they’ll be sued as well?

  16. The KelTec magazine was a chopped down S&W 5906. Nothing more. It’s not magical. There was no special innovation there. KelTec was an evolution of the Grendel and is an unprotected design. Hence the myriad of KelTec looking pistols (SCCY, Ruger LCP/LC380/LC9, Republic Arms, etc). The shield arms mags just use the outer dimension of the polymer mags with thinner steel walls and utilize the extra interior space to hold more rounds. No space magic required.
    The P365 is slimmer than a P11 and holds 12 rounds. That is the difference that SIG will claim. Do you think Ruger, Smith, and Springfield Armory all looked at the P365 and carbon copied it without consulting a patent attorney?

    • The P11 magazine also holds 12 rounds (basic one 10, but identical ones 12, I have both), and will insert into the P365 mag well. Therefore, there is nothing special about the Sign magazine.

      Sign just made a better quality gun than the P11 (and slightly smaller firearm).

    • SIG’s standard (not XL) flush-fit magazine only holds 10 rounds.

      The miniscule difference in grip width is literally the deep checkering on the P-11. Magazine width is basically identical (actually .01″ wider for SIG).

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