3D Printing an AR Lower Video

We’ve posted a lot about 3D printing here on TFB since it started to make waves in the news. From 3D printed AR lowers and bullpup prototypes to metal 1911s, but how does all this newfangled 3D printing actually work? Youtuber Barnacules Nerdgasm goes into detail on how-to actually 3D print an AR-15 lower, it’s a pretty good watch. He also tries to clear up a lot of misconceptions that the mass media likes to throw around when it comes to 3D printing and firearms in general.

Ray I.

Long time gun enthusiast, archery noob, Mazda fan, Sci-Fi nerd, Whiskey drinker, online marketer and blogger. My daily firearms musings can be found over at my gun blog ArmoryBlog.com and Instagram.

Shoot me an email at ray.i@staff.thefirearmblog.com


  • 1leggeddog

    The thing he doesn’t talk about is the legal side, which is the most important part of this whole debacle.

    The lower is considered the firearm in the legal sense so ya, he just created a gun. Sure, It’s missing everything else, but it’s still legally a firearm.

    Now correct me if i’m wrong, but everything else can just be bought and shipped to his house no questions asked.

    No background check or license is needed to buy a barrel, upper or trigger mechanism.

    His best quote is about the durability of the whole thing. Because you can do it, doesn’t mean you should do it, just for safety reasons. But that’s imho.

    • UnrepentantLib

      The law gets kind of interesting with regard to building a firearm. AFAIK, it’s legal to build a firearm for your own use, provided the firearm is legal in your area, you’re not prohibited from owning a firearm, and you put a serial number on it. The catch is you can’t sell it. Also, the receiver can’t be more than 80% complete when you get it. The reasoning being, I suppose, that building a firearm means having a level of skill beyond just screwing parts together. It’s going to get real interesting when 3D printing develops to the point of using durable materials.

      • iksnilol

        You can sell it (that is why you need a serial), you just can’t make it for the express purpose of selling it.

        Also you don’t need a serial number if it is for private use, only if you later on decide to sell it.

        NOTE: Am not a lawyer, consult your legal advisor before procceding.

        • 1leggeddog

          Up here in Canada, the same ruleset applies, except for the selling part. Its yours forever. Non-transferable without a manufacturers license.

      • John

        You can print out of stainless steel already. You can even got stainless steel with a gold like finish for the ultimate bling AR-15.

      • gunslinger

        you don’t need to serialize at the time of manufacture (for personal use only) if at some later date you decide to sell, a SNO must be affixed.

    • JumpIf NotZero

      No background check is needed to build a gun. No questions asked.

    • Ben

      That is the entire reason Defense Distributed put up the Liberator pistol and AR-15 lower plans. To demonstrate just how silly current firearms laws are.

      He’s right that it isn’t really cost effective, and requires more work than just buying a lower. However, it means no paperwork, and is legal (depending on locality).

  • Joe

    Yeah, I don’t think 3D printed lowers are going to be practical for the next 5 or so years, with the possible exception of that bullpup lower for non-buffer tube AR-15 uppers. The materials for commonly accessible 3D printers just don’t have the strength to put up with the stress right now. Once polymer and/or metal 3D printers become common, then 3D printed guns will be worth talking about.

    • JumpIf NotZero

      DLMS. Could be making titanium lowers right now.

      SLS can make poly lowers as strong as anything else we’re seeing on the market.

      It’s not really an X number of years thing. 3D printing isn’t supposed to be practical, it’s supposed to be proof on concept for prototypes.

    • iksnilol

      What is going to be practical is printing triggers for homebuilt firearms. Much easier to print a trigger and use a couple of springs from pens and the like than making one piece by piece from metal.

    • sauerquint

      Wouldn’t it make more sense to use the 3d printer to make receiver molds?

  • Should have try 3d printing the Upper …. and then fire it, the smile/shock on the faces of the ones surrounding you is PRICELESS

    • 1leggeddog

      by smile/shock, surely you mean shrapnel?

      Printing the lower is one thing, it’s not under direct stress from firing, but the upper houses the BCG which IS. The rails on which the BCG rides will wear through the polymer. Defects will cause recoil to warp and go kaboom because it wont hold the bolt correctly closed at one point.

      Prove me wrong but it just doesn’t sound safe.

      • BryanS

        Depends on what you print it from. Some of these guys have access to machines doing nylon.

      • patrickiv

        Even the upper receiver isn’t under very much stress. The most stressed part is where the bolt and barrel extension lock. I would be more concerned about a the gas tube getting hot enough to soften the thermoplastic, which becomes a liquid at less than 300 degrees C.

  • John Sjöström

    Should be easy to 3d print a polymergun like the UMP or G36. Now thats a 3D print I would like to see.

  • BryanS

    Let me tear this apart…

    First, use something like meshmixer so you don’t have to remove all those wasted supports. You would end up with a much better / closer print.

    Second, you dont print out of PLA. You print out of ABS at minimum, and use a solvent to fuse layers better.

    And if he read the defcad forums (where they are using similar printers to what he is using) they talk about proper scaling for different materials.

    This guy is in kindergarden, an the defcad guys are in Princton. And his video is about 10 minutes too long. Very annoying.

    • BryanS

      AND he puts magazines in like “As seen on TV” people handle real tools.