The response to the settlement between Cody Wilson’s DEFDIST and the State Department has been nothing short of excessive, for a variety of reasons. If you listen to the right broadcasts, and read the right articles, no one could blame you for thinking that there will be blood in the streets. A district judge in Washington state has issued a temporary restraining order to keep DEFDIST from distributing their files through the DEFCAD portal. Leaving aside the obvious technical problems in his reasoning (the cat is well out of the bag, and trying to stuff it back in just invokes the Streisand Effect), and potential legal issues (at least one SCOTUS justices is less than equitably inclined towards universal injunctions issued by lower courts, not to mention that this WILL get challenged on first amendment grounds), there is absolutely no reason for preventing the distribution of the DEFCAD files.
There are two ways to make a gun with a 3D printer. The first is to 3D print the entire gun. The type example of this is Cody Wilson’s Liberator pistol (named after the WWII era gun). As with it’s namesake, it is a single shot pistol with limited uses, albeit in a smaller (and not terribly adequate) caliber. It is useful mostly for causing freakouts by people who don’t realize how useless it is. Most of the freaking out seems to be due to the the fact that it’s plastic, and the chunk of metal included in the design isn’t structural and can be removed (illegally) without adversely affecting the gun, making a weapon that could theoretically slip past a metal detector. Just what someone is going to do with only one or two rounds of ammunition and a single shot handgun I’m not sure, but it isn’t going go well for them. I’d be more concerned by all the Swiss Army knives , actual useful guns and high explosives the TSA keeps missing. There’s no point in getting all worked up over a single shot, single (assuming you want to keep your fingers) use pistol when it seems like pretty much everything else already gets past the TSA.
The second method of making a gun involves making a receiver (or lower receiver, depending on the gun), which, in a factory produced gun would be the serialized (with exceptions, home made firearms aren’t required to be serialized) and controlled part. AR-15s are quite popular for this, due to the ease of assembly and a multitude of interchangeable options. Of course, most of those parts are metal, so your homebuilt AR isn’t going through any metal detectors. It is, however a useful gun… but people have been building them in their garages for decades, using everything from plastic, to wood, to the traditional aluminum, and even steel, using various tools and techniques, some of which wouldn’t be out of place in the late 19th century.
In fact, 3D printed firearms should be very far down anyone’s list of priorities, and that includes people who want to get rid of guns. Slamfire pipe shotguns are significantly easier, have a lower entry point, have a very minimal cost per build, and require no specialized knowledge to produce. Open bolt submachine guns have been produced using common tools and materials purchased from a hardware store, and there are a multitude of how to manuals that make it so you need only minimal knowledge for production. There are even a couple that are aimed at mass production, as opposed to small and individual scale production. This particular brouhaha is about sixty years out of date.