VLTOR sues Magpul

Abrams Airborne Manufacturing, VLTOR’s parent company, is the third company in recent months to sue Magpul over patent infringement. VLTOR claim that Magpul’s ACS stock violates their Modular Firearm Buttstock patent.

VLTOR’s Modular Firearm Buttstock – Patent 6925744
Magpul ACS

Both stocks feature a removable storage compartment. It looks like VLTOR may have a legitimate case.

[ Many thanks to jdun1911 for emailing me the link. ]

Click through to view the lawsuit and patent … (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.


  • Haven’t the time to read the legal document but the two stocks look different enough to me. VLTOR’s is adaptable so that you can keep one or both of the storage compartments, a feature not found on the (patent pending) Magpul stock.

    From where I’m sitting it looks like the basis of the case is the idea of storing items on the stock nestling under the buffer tube extension. Other than the location of the storage compartments the two stocks aren’t similar at all.

    Steve- you say they both feature a removable storage compartment but from looking at the Magpul site the compartment on the ACS isn’t removable.

    Or am I missing something?

  • Canthros

    The compartment on the ACS can be removed, but I don’t think Magpul had that in mind when the designed the stock. The cynical part of me wonders if the ACS isn’t cutting into sales of VLTOR’s *MOD stocks.

    I have a feeling that VLTOR loses either way, though. If they lose their lawsuit, things carry on as they are. If they win the lawsuit, Magpul redesigns the stock with two fewer parts and almost the same external appearance.

  • DavidR

    I agree with Jay-Mac and I don’t the the infringement.

    The VLTOR looks and functions much more like the LMT SOPMOD stock. Has that lawsuit ever happened?

    Seems like Magpl might just be fun to sue…

  • DavidR

    Could the lawsuit be over the other storage compartment?

  • EzGoingKev

    So VLTOR is suing Magpul claiming they copied their copy of the SOPMOD stock?

  • D

    I dont see how the ACS storage compartment is removeable?

  • I just think some companies are jealous as of late.

  • The small trap door compartment in the toe of the stock does not come off on the ACS. The UBR one does.
    The only removable storage on the ACS are the battery tubes, and after a few minutes of looking over mine, I can’t really tell how you’d take them off anyway.
    The ACS is most definitely cutting into their sales, those of us with beards don’t like having the jigsaw pattern connection point of their battery tube ripping hair off our face. The ACS doesn’t do that.

  • david l wisz

    From the AAM Patent, 6925744, the key elements which need to be found on the alleged infringing device (magpul ACS ) would be:

    “said buttstock including a frame wall and one of a series of openings and a series of projections extending along said frame wall between said forward and rear ends”


    “said buttstock accessory including an accessory wall and the other of said series of openings and said series of projections extending alone said accessory wall; said series of openings and said series of projections being adapted to interengage one another and at least partially secure said buttstock accessory on said buttstock frame”

    It would appear that the MagPul does have the “series of openings and said series of projections” between the tube and the buttstock


    This is not an official option in any sense, but a quick review only. I would suggest that with that caveat in mind, Infringement does appear quite likely.

    David L. Wisz
    Intellectual Property Attorney
    CG&O, P.C.
    400 W. Maple Road, Suite 350
    Birmingham MI 48009

  • Bandito762

    Is there some sinister plot here to bury Magpul in legal bills with frivolous lawsuits. It seems to me Magpul may have copied the concept but did it in a completely (and in my opinion more attractive) package. I have never handled either stock personally, but I think Vltor may just be smelling the blood in the water.

  • JKEverett

    After looking through the documents and VLTOR’s patent I’m not sure how the Magpul stock is infringing on their patent. It seems that the crux of the mod-stock is the ability to interchange the storage compartments and other components. The ACS doesn’t seem to have the same modular system.

    Magpul is a great target for litigation, though; they’re expanding quickly and they’ve managed to corner a good portion of the market.

    Ultimately, Magpul can’t 12(b)(6) this suit because Abrams has stated a claim. Depending on how Magpul responds to the complaint may make summary judgment available – although there may still be a genuine issue of material fact regardless of how Magpul answers.

    All things considered, Magpul is going to have to spend a considerable amount of money litigating this, regardless of its merits…

    Kinda annoying, really.

  • Ty

    It’s too bad that Vltor thinks they can’t compete in the marketplace. I guess people just don’t want to buy their stuff so they have to sue people that are doing well.

    Seriously this is about sticking a little door on a buttstock? Patent law can’t get more stupid than this. That’s not something that can even be patented. I have a wireless mouse that has a battery compartment for storage, is Vltor going to sue Microsoft?

  • Garibaldo

    Full disclosure: I’m a patent attorney, so brace yourself for some boring legal analysis …

    To decide whether a product infringes a patent, you have to read the “claims” of the patent. The claims are the numbered paragraphs starting at column 12 of the patent (p. 29 of the .pdf if you download it). The patent covers a buttstock where an “accessory” (it doesn’t have to be the storage compartment 104, can also be the cheek weld adapter 118 or just about anything else you might call an “accessory”) is attached to the frame using “openings” and “projections” on both the frame and accessory that interlock with one another. These are, I think, the teeth (116 on compartment 104, 130 on adapter 118) and the rectangular holes 154 on the buttstock frame (see Fig. 7).

    I’ve never seen any photos that show how the storage compartment is attached to the frame on a Magpul stock, so I can’t comment on whether or not I think Magpul infringes the patent.

  • Grey

    Interesting. I think VLTOR is out of order here…

    Adjustable buttstocks are nothing new. Fairly standard equipment these days, anyhow.

    Accessory compartments in rifle stocks are nothing new. Folks have been doing this for at least two hundred years.

    The Magpul battery storage compartments may look removable. They may be removable. But the method of their mounting appears different. Also, the method of their function and opening appear very different. The added built in storage compartment at the tail of the stock also apears very different.

    I don’t see VLTOR winning this one. Not in a million years. They smell desperate.

  • Grey

    I suppose it could be for the tail stock compartment, but that isn’t in the diagrams and documentation in their brief, at least not at a cursory glance. Even so, the Magpul compartment opens in a different manner, and on the right side of the rifle. I still don’t think VLTOR will get a lot of traction here. Seeing as how Magpul also has a patent pending status, I am sure they went over this pretty carefully.

  • Trango78

    I gotta echo some of the other comments here. VLTOR did not invent the wheel when it comes to their stocks. As great of stocks as they may be, VLTOR took the SOPMOD stock and made it their own with a few other features.

    I think Magpul has simply improved upon the VLTOR/SOPMOD stocks by taking the best features of both and adding their own touch.

    It could be possible too that the “changes” Magpul made to the ACS allow them to work around the VLTOR patent.

    In any case, I think that Magpul has become a target because of the enormous growth and popularity they have seen in all markets of this industry.

    I guess the theme is, if you can’t beat’em….sue’em.

  • Lance

    I didnt care I thought both stocks are acward and uncomfortable.

  • Burst

    The Magpul version, of course, has the advantage of not looking like absolute ass.

    Gotta love a company that decides it’s time better spent on lawsuits than actually remaining competitive.

  • jdun1911


    I think you’re right that it is between the Vltor’s Emod vs. Magpul’s ACS.

  • Travis

    Did you guys look at the image posted by the first patent lawyer? Its the way the battery compartment connects to the stock. Thats the similarity allegedly infriged upon. The Vltor you can see many teeth or fingers which sort of dovetail together connecting the stock and the compartment. Magpul has the same thing, but less teeth. Is that enough? The courts and lawyers will find out.

    Look at the image:

    That shows the Magpul compartment attachment.

    Yes both are based on the Crane SOPMOD stock, but that does not have compartments which detach the same way.

  • david l wisz

    Here is a photo of how the ACS at least partially attaches:


    Notably, nowhere within the claims is removability required. Only “said series of openings and said series of projections.” From the Picture, the ACS seems to have this element.

  • Yossiarian

    Attaching two pieces of plastic using teeth or fingers which dovetail together is a common process of manufacture and is too obvious to be patentable (or at least to be upheld in court).

    Also “said series of openings and said series of projections” suggests more than two openings in order to create a “series”. The Magpul stock has just two opening on the referenced side.

    Seems like a weak case to me.

  • Legitimate only in a world gone made with lawyers (which sadly this is)…

    Frankly, those are not inventions. And should not even have received patents.

    Heck, I am just waiting to be sued for driving my car by some guy with a patent on the wheel.

  • Warpig1

    My understanding of patents is like everyone else. History. The courts have usually said that the violation has to be very narrow and exact. Vltor must be Judge shopping as we speak. The U.S. patent office issues too many almost just alike patents and they know it.
    Vltor can innovate or die. This is a desperate move. Anti competition is anti consumer. We loose, so everyone should boycott Vltor products.
    Too bad, since I liked Vltor products. They must have gone through a brain drain there. Why doesn’t Vltor copy (not copy) Magpul? Get it? Its a War!
    Did anyone else notice how wordy and yet vague the Vltor wording was in their patent filling? They wrote it that way so as to preserve a future lawsuit. LMT should now sue Vltor! The patents should have been rejected as to not being clear and specific.
    One last thing for us consumers. Everyone who can should try to trick Vltor and Magpul employees and owners into talking their heads off before trial. You know who you are people. Get to work! This is the best tactic to FFFIng up the suit and stopping it. Yaa! (No, I do not work for Magpul)

  • jamie

    Guys modular means parts that are the same, you put them together to made a larger unit or gain function. The basics are the same, a few details create a new unit. Like ford calls their v8 system a modular v8, it was designed back in the 80s, to be a 4.6, 5.4, 5.7 etc. Same block, the modular part is using a few different parts. Not the best example but it is a consumer product with modular in the name.

    Like modular wall parts in semi finished stick built homes. You buy pre hung studs, exterior wall, foam, etc, and bolt them up. You can order the same wall 4×8 with door opening or window opening, or blank opening for custom feature.

    I think the modular part is the cheek riser.

    You can patent a use, like uncle mikes has the patent to a pistol fanny pack.

    Others can make them, if they have a license agreement, and pay uncle mikes a $1 or $2 for everyone that is made.

    You can patent an application of existing idea or product. A guy has made a fortune patenting the ear foam plugs. He neither invented foam, or ear plugs, he simply thought of making foam ear plugs. He is rich.

  • True Innovator

    Magpul rips everyone off. That is how they get their product line. I know for a fact! Innovative, I think not.
    As petty as all these legal battles are, they are for a good reason. People who come up with a good idea deserve to be able to profit from it without everyone copying their ideas. Magpul is in the process of copying mine right now and it will put me out of business once it happens. I used to think they were great but later realized that they just steal other peoples ideas and have the money to release them on a larger scale for bigger profit, hence can afford the attorneys to defend their plagerant practices. Yes they can be creative, but I do honestly believe that they are not innovators but rather followers with a bigger bank roll. They might as well be from China.

  • matt


  • surfgun

    Any update on a disposition?