Lego Brick AR Stock

As a fan of Lego and firearms I am not sure if it is a good idea to make a hybrid of both. Alloutdoor posted this the other day.

Feinstein Gewehr Werke, LLC, is a plastic brick kit manufacturer. They make the Mk8 stock for milspec buffer tubes. The kit costs $40 plus s/h and tax. They posted free instructions online to build the stock. The stock is not just lego bricks attached to each other by their clutch power. Clutch power is the ability of its bricks to snap together tightly while also being easy to separate, thereby readily allowing for de- and reconstruction. Feinstein Gewehr Werke uses super glue, epoxy and steel rods for support.

lego-butt-stock-660x470 markingTheThreadedRod mk8Prototype

IMAG0568 IMAG0566

The multi color nature of the stock is due to costs. You could look at the instructions and figure out the parts required and order them through online resellers of individual bricks, like

According to the website, the makers of the stock tested the Mk8 on a Remington 870 12 ga with 24 rounds of 3″ magnum 00 buck.

Here is a link to their video.

The design of this stock and the lack of any recoil pad makes it look extremely uncomfortable to shoot. Especially with a shotgun.

They are also working on something they call “The Feinstein Project“. Building an AR lower out of Lego bricks. If you click on their “Lines of Effort” you can see some baby step projects that could lead to a functioning lower.


Nicholas C

Co-Founder of KRISSTALK forums, an owner’s support group and all things KRISS Vector related. Nick found his passion through competitive shooting while living in NY. He participates in USPSA and 3Gun. He loves all things that shoots and flashlights. Really really bright flashlights.

Any questions please email him at


  • Vitsaus

    If they get the lego lower off the ground, that would make my year. I know its probably not going to work, but the amount of hide chapping it would cause with antis would be monumental. Just imagine the overnight ban on legos. Imagine the scramble to get form 4473 into toy shops for lego buyers.

    • MR

      Hope they build a custom buffer tube, rather than using a boring (and expensive) big-azzed drill bit and tap.

  • TheNotoriousIUD

    Non-adjustable, uncomfortable, ugly and expensive.
    I’m in!

  • Hokum

    What’s more important is that you should NEVER step on it!

    • wetcorps

      “don’t thread of me” starts to make a lot more of sense ^^

      • iksnilol

        Somebody should make a Gadsden flag with Lego pieces instead of the snake.

        • Cymond

          Or a 3d Gadsen statue made of Lego

  • iksnilol

    Sorta defeats the spirit of Lego by requiring you to glue and epoxy the bricks.

    • SP mclaughlin

      Not purist 🙂

      • iksnilol

        A long time since I heard about people complaining about stuff not being purist in Lego… I should know since I was one of the people complaining 😛

        • SP mclaughlin

          I found it rather funny how the Lego movie portrayed glue as the antagonist’s tool.

  • MR

    Somebody needs to teach that kid some trigger discipline.

  • Alex Nicolin

    Feinstein’s gonna ban it, and introduce federal permits for LEGO bricks.

  • sam

    I think I’d have used un-threaded rod. Splined maybe.

  • tazman66gt

    Makes me want to get all my old Lego’s back from my aunt, lol

  • Aurek Besh

    I would recommend using Technic pieces rather than the standard bricks. With proper studless building techniques, the parts are held positively by interlocking pins and axles rather than just friction. The bricks remain unmodified, no cyanoacrylate or threaded rods needed.

  • mzungu

    Maybe this bright color will be a great way to disguise it as an air gun. Keeps the cops guessing. 😛

  • Greg Bowling

    There are Technic pieces in the stock, as 10-24 threaded rod is nearly a perfect fit in Technic holes, w/ the super glue nicely filling in the spiral and making a solid connection. Please forgive Grayson his excitement, as there was no bolt in the rifle @ the time of the photo. We’re using a mil-spec buffer tube, which does not come with the kit.

    With the light recoil of .223″, the stock is not uncomfortable @ all & provides a decent cheekrest. W/ 12 ga 3″ 00 buck… (the video is on the website)

    The Feinstein Project is an attempt to build a functioning AR lower out of plastic bricks & other materials. The Strike Industries trigger jig comes to mind…

    Thanks for the interest and the links. I read TFB regularly, & missed this post ’til today.