Printed Arms Primer

A brief explainer on the state-of-the-art in printed firearms.

DISCLAIMER

DO YOUR OWN RESEARCH IF YOU’RE MAKING A GUN. I AM NOT LIABLE FOR ANY CONSEQUENCES OF THIS INFORMATION. THIS POST IS NOT GUARANTEED TO BE 100% ACCURATE.

Can 3D printers produce a useful firearm?

Yes. Caveat: no useful firearm is entirely plastic. Or, any entirely-plastic firearm will be extremely limited in firing multiple shots.

The most advanced printed firearm you can make is the FGC-9 pistol-caliber carbine. It can be made with a $200 3D printer, parts you can buy at any hardware store, and actual firearm parts you can buy online. Check out the release trailer for a quick look at what it can do.

I am claiming the FGC-9 as the most advanced printed firearm because it’s comparable to a “real” manufactured pistol-caliber carbine due to the advanced home manufacturing techniques developed for it. Most notably, the FGC-9 developers created a technique for rifling a barrel at home using electrochemical machining and 3D printed parts. A rifled barrel will be more accurate than a plain steel pipe, though since I haven’t made or tested this technique, I can’t quantify the improvement. The FGC-9 also has a high proportion of printed parts, compared to our second category of useful firearm: the printed lower receiver.

A lower receiver is the part of a firearm that contains the trigger mechanism, fire control group, and magazine well. It controls how bullets are fed and fired from the gun. Under current American law, the lower receiver is the part of the gun that is legally considered the firearm. And, lower receivers are 3D-printable.

Yes, you can make guns at home. But they are legally required to have some metal parts. That’s it. No serial number necessary. This only applies if you are legally allowed to own a firearm, though! Felons, for example, cannot manufacture firearms for themselves.

The Gun Control Act of 1968 states that it isn’t illegal to manufacture a firearm for personal use. A very relevant law to 3D printing legal firearms is the Undetectable Firearms Act of 1988, which makes owning or manufacturing any firearm undetectable by a walk-through metal detector (so with <105g of steel) illegal. The ATF confirms this in their FAQ.

Huh? Making guns…at home? Is that possible?

Yep! It’s possible with traditional subtractive manufacturing as well as with additive 3D printing. The subtractive way is with an 80% completed lower receiver: drilling holes for a fire control group makes the receiver a functional firearm. 80% lowers and rifle parts kits are not expensive! They start at about $600-$800, but do require some mechanical skill to assemble. Again, the printed arms community also helped improve method: jigs for guiding drill holes are available online, and the Ghost Gunner desktop CNC mill can finish a variety of 80% lowers automatically.