Defense Distributed Releases Printable AK Magazine

The fertile minds at Defense Distributed have announced the existence of The Feinstein Mag. Available for free download from their website at, The Feinstein Mag is not a magazine, but a computer file which can loaded into a three-dimensional printer. When the file is accessed and its program run, the 3d printer will print out as many 30-round 7.62×39 AK-47 magazines as the printer operator wishes. The program includes everything needed to print out the magazine body, follower, and floorplate; only a metal spring needs to be sourced separately to assemble a working Kalashnikov magazine.


Defense Distributed made national news not too long ago with their upgraded, reinforced AR-15 lower file, which allows a 3d printer to create a working AR-15 lower receiver. They also have The Cuomo Mag, a 30-round AR-15 magazine, and other firearms related files such as a sound moderator and magazine coupler. There is even a file for a complete .22lr single shot pistol reminiscent of the famous WWII “Liberator.”

Defense Distributed’s stated goal is to destroy gun control efforts through the widespread sharing of information. Regardless of what laws may be passed, gun control efforts will fail if the citizenry cannot be physically prevented from possessing or manufacturing firearms and their components. Gun advocates like to say that the 2nd Amendment protects all the others. Defense Distributed intends to prove that the 1st Amendment can protect the 2nd.


  • “You can’t stop the signal, Mal.”

  • thedonn007

    So, how does making your own mag, make it legal to have and use?

    • Tom

      Most laws just ban the sale of certain magazines, not the manufacture. So as long as you don’t manufacture them for sale you’re good.

      • Ray

        And even if they ban manufacture it goes to show that the whole arms control meme is essentially is a frivolous pursuit. I have the diagrams and schematics for an AR-15 standard capacity magazine and the follower to go with, I could easily produce enough for myself with a bench press.

        • Bingo. I did a radio show at my old college about 3 weeks back where I tried to drive home that magazines are just boxes with springs. It doesn’t take a rocket scientist or a super advanced manufacturing facility to make a magazine. People forget that manual mills were (and probably still are) used to make sophisticated firearms such as the 1911 along with a slew of others. IMO, the single most technically challenging piece of a firearm to make is a (proper) barrel.

          • lolinski

            That is why barrels are controlled here in Norway :(.

          • Ray

            They can’t control mechanical seamless tubing and machine tools!

          • Komrad

            And a shotgun doesn’t need much of a barrel.
            Semi-auto shotguns with cylinder bores would be stupid easy to make with a manual mill and lathe and even easier with CNC.

      • John184

        So in theory, you could just give the owner of the printer the plastic needed, and he can give you the finished magazine for free? Bartering doesn’t necessarily equal sale, right?

        • That’s not barter as barter implies trade. If you were to say “I’ll give you this plastic and a beer and you print me a magazine” that would be barter and it might constitute a sale.

        • sianmink

          You can just rent time on his printer, buy materials, and go to town.

    • Komrad

      It doesn’t. Just like Silk Road doesn’t make drugs legal and foreign hosting of pirated media doesn’t make copyright piracy legal.

      What it does do is render the laws ineffective and unenforceable.

  • I’m so tactical, I’m a “printer operator”.

  • P161911

    So does the floorplate work with standard steel AK mags? I need some MADE IN USA floorplates for a couple of AK projects. Growing my own would be cheaper and easier than buying them.

    • Paul Henning

      It’s made in the US, you printed it. You can also alter the cad files to show you comply with that stupid law if you must but really, legally, you don’t need to it was clearly extruded here in the US.

  • NorThor

    I would never use one of these. The plastics that they use in 3d printers simply aren’t durable enough for any sort of gun parts.

    • Paul Henning

      I’m sure people like you scoffed at the idea of the pmag. ABS handles well for a few uses and thats what counts.

      • Ian

        It’s not entirely the plastic type, it’s the manufacture method. People like him probably loved the idea of a Pmag (the only innovation being the curved inside as opposed to its many plastic predecessors). Molded ABS would be fine. Printed ABS is crap.

        • Suburban

          How difficult would it be to make a mold of a magazine tube from a printed ABS part? Or from an existing polymer magazine for that matter? I’ve seen mold kits for sale, but never tried it.

    • snake

      I agree with you and I believe metal 3D printer is coming soon

      • Blastattack

        Direct Metal Laser Sintering devices, or “metal printers”, already exist. They cost a fortune, but they exist.

      • As Blastattack stated, they already exist (and have for some time). The issue with SLS isn’t so much the cost of the machine (which can/will fall with time/scale) it’s more in the amount of energy that the laser consumes (not trivial) and the cost of the feed-stock. I don’t see how metal powder (which must have a specific grain size/shape to work in these printers) will ever be low cost.

        • Eric S

          They way they currently work is by extruding a binder into metal powder. The there is a process of reverse osmosis with liquid metal in an oven, the specifics of which elude me and I think there is voodoo involved. But the process is still young and as the tech gets more widespread new innovations will crop up.

      • Avery

        If you know some home blacksmithing, you could just sandcast the parts. Pour molten metal into the cast and it vaporizes the plastic parts. There would be very little difference between an aluminum receiver milled or cast, as long you get the right aluminum (like from car engines or sports equipment).

        • If you’re casting it out of aluminum, you wouldn’t want something as solid as they used for the mag we see, it wouldn’t evenly melt/vaporize it and would displace the casting sand in the process. I’ve never seen good results using solid ABS plastic, even vibrating the mold as it’s poured leaves voids and occlusions that run the casting.

          Thin foam slabs, on the other hand, could be measured, cut to shape, and glued together and then replaced by aluminum quite easily. Since it’s mostly air in the first place, there’s less expansion of the plastic as it works it’s way out.

          Either way, the biggest problem is that you really can’t perform any sort of finishing other than maybe a light polish on the inside of the cast magazine, it’ll be somewhat rough and that will no doubt interfere with the function of the follower.

          • Avery

            The thing I’ve heard to use is PLA or PVA, which are bioplastics. The other thing is that, if you’re making magazines, you don’t even need to get that technical. I’m pretty sure you can print out molds, then use that with resins or cold-temperature casting powdered metals. I was about to ask someone if something like powdered aluminium or powdered brass could work for something like this. I wouldn’t trust it in a receiver, but a magazine maybe can hold up.

            One of the things that’s a bit disappointing about DefCAD is that they’re more concerned with what you can directly print out and not what you can indirectly make with a 3D printer, like molds and investment casts.

          • If we’re talking about making molds, I can’t see any advantage a 3D printer would have over a CNC mill, it’s got a much wider range of materials available and the mold would be sturdy enough to crank out a series of magazines. You’d be essentially making a reversed version of the CAD file and then cutting it out of a block of steel or whatever is appropriate for the material you’re casting. Making magazines with a 3d printer only makes sense if that’s the entirety of the process, once it’s more complicated other techniques win out.

            One thing I’d be interested in seeing in the future, though, is a way of 3d printing a mold/scaffolding and then pouring the material for the casting with the same machine as a single continuous process. You’d have to print in some sort of heat-resistant material, pour, and then remove it either with a solvent of some sort or shatter it and pull out the bits and pieces.

          • Komrad

            You can build a rather inexpensive Rep-Rap 3d printer for a few hundred bucks with some know how. Although you can do the same with a CNC.

      • Ripley

        Why print metal when metal milling/sculpting machines can do anything today? Search “5-axis cnc metal” on youtube. Those can probably make any gun part you can imagine, and engrave it at the same time.

        • Suburban

          The 3D printer stuff is something most people can do on their kitchen table with a few hundred dollars. A basic, manually-operated Chinese mini-mill runs about $600. Grizzly’s cheapest CNC, a 3-Axis, is $28,000 and weighs 3332 pounds. I’ve seen smaller milling machines, converted to CNC, for a lot less, but this is way beyond what most people are capable of doing, and completely impractical $wise unless you’re going into business.

    • Will the magazine last through a war? Probably not.
      Will it be as reliable as something factory made (bakelite etc)? Probably not.
      Will it be 95+% reliable for a few hundred rounds? Probably.
      Will it work in a pinch? Yes.
      Is it better than not having access to a 30rd magazine at all? IMO, yes.

      • Joel

        Materials science will likely continue to improve.

    • From a design perspective, these mags will have problems with the feed lips and the magazine catch… The lips will go first. My guess is that they’ll be good for 20-30 uses. Maybe a bit less. Still better than nothing.

  • IMO they should make a lower with an integral grip, stock, and buffer tube (ala Cav Arms lower). Hey, wait…. I work with Autodesk Inventor all the time. Maybe I’ll do it next weekend 😀

    • Ray

      You know, I was thinking something akin to the Magpul PDR-D and C, worked on so that it works well with a 3D printer would be just the ticket. The internals would probably need to be made from metal, a small desktop CNC is affordable and relatively low profile.

      I’m seeing a working area the size of a small bedroom just for the machine tools needed to get a rifle, barrel and magazine production + if you was to automate a progressive press…

  • WFM

    Product liability…..

    I hope the designs available are well tested and the failure mode is not catastrophic.

    I can see the lawyers having a field day with this.

    • Komrad

      How could the mag catastrophically fail?
      It could break if hit or dropped maybe, but it isn’t under any pressure or much stress.

  • You can’t put the tooth paste back in the tube.

  • Badass! Keep up the good work!

  • phamnuwen

    Instead of building parts for existing gun designs it might be worthwhile to design a firearm from scratch that is designed with the printer plastic in mind, to make it durable.

    Also, by all means, don’t restrain yourself to rifles. A belt-fed machine gun would be nice. Or a grenade launcher. Or a belt-fed grenade launcher. Or all of the above.