

Once again, the imminent publication online of instructions and CAD files for the 3D printing of plastic guns has stirred up lots of news coverage and controversy. The US has settled its case against Defense Distributed, which plans to publish blueprints for 3D printing at least one and maybe more plastic guns on August 1st. While the event makes for a convenient milestone and talking point, the truth is that there are now many ways to create a variety of guns at home or in a small shop, and almost no agreement over how they should, or shouldn’t, be regulated. 3D printing is merely one of the newest and attention-getting. Our aim in this article isn’t to make a particular political case about the situation, but to provide some background on current technologies and policies in the area, and how they are evolving over time.

Customizing or Building Your Own Firearm

3D-printed AR-15 lower receiverFor decades hobbyists have delighted in customizing guns of various kinds. Two of the more popular platforms are the AR-15 style rifle and the Ruger 10/22 rifle. Customization typically starts with either the purchase of an inexpensive “stock” model or a regulated lower receiver component. From there, everything else you need to create a fully-functioning weapon of your own design is easily available as an accessory online or from a local store. When California recently passed a Proposition curtailing the sale of some weapons, including AR-15 style rifles, beginning this year, gun dealers sold boatloads of lower receivers late last year to hobbyists who wanted to stock up for the future — as those receivers will be grandfathered and can be built into complete rifles later.

However, not everyone wants to purchase a regulated component or stock model to get started, so a cottage industry has formed that sells “80 percent receivers” that are close enough to the final product that they can be finished with some work in a small shop, but not close enough to need to be regulated as firearms. This used to be considered tricky to do on your own, but more recently lots of DIY videos and kits have started popping up. Defense Distributed, the same company that plans to re-publish its 3D printed designs, even sells a CNC machine that will do the job of turning a kit component into a functional lower receiver in an hour.

DIY Guns Live In an Unregulated Niche

There are limits to what you can legally do with a gun you’ve created from a kit that doesn’t include a registered receiver. You can’t sell it, for example. So it’s illegal to go into the manufacture of these guns for sale. But you can make one for yourself and use it, as long as you don’t run afoul of other laws.

The danger of DIY weapons allowing those who might not otherwise be able to purchase a firearm to obtain and use one was brought home when mass shooter Kevin Janson Neal used rifles he assembled himself in a mass killing. Given his medical history, it is unclear whether he would have been allowed to purchase similar weapons legally. Since it’s also currently legal to sell all the pieces needed, it means that there is currently a legal way for guns to proliferate despite various state and local efforts to curb the sale of weapons.

It’s Plastic That Makes 3D-Printed Weapons Scary


A disassembled Liberator pistol from the original 3D files before they were pulled.

Much of the attention paid to 3D-printed weapons ignores the current state of available 3D printersSEEAMAZON_ET_135 See Amazon ET commerce. Sure, if you have a six-figure metal printer you can make some pretty nice guns, but it’s a lot more work and expense than simply milling the key parts and buying the rest. Even if you print the receiver, for example, some parts like a reliable barrel are beyond the reach of any affordable printer. Current plastic designs are also fragile, potentially dangerous to the person firing them, and have a limited service life.

However, plastic weapons also have the potential to be undetectable using standard metal detectors. That makes them particularly scary to anyone in the security business. The Undetectable Firearms Act of 1988 took an initial shot and dealing with this issue. It requires that a legal firearm contain enough metal to set off a metal detector. However, attempts to update it to address modern technology (like the version floated by then-Congressman Steve Israel from New York) have failed repeatedly. For example, the Act doesn’t say that the metal part has to be intrinsic to the weapon’s operation. So it can be interpreted as meaning the metal part can be removable — perhaps for long enough to get through security.

DIY Weapons Are Scarier to Countries With More-Restrictive Gun Laws


The original FP-45 Liberator, produced by the Allies in WWII for resistance fighters in France and China.

Looking at the worldwide situation, countries that have worked hardest to reduce the number of guns are at the most risk from DIY guns of any kind. Here in the United States, it’s relatively easy to acquire a firearm, either legally in most cases, or even illegally. So it is unlikely that DIY guns will make a massive difference in the total number of guns.

But in countries like Australia, with very stiff gun laws, the effect could be profound. To address that issue, Australia has passed a law providing for up to a 14-year prison sentence for the possession of plans for a 3D-printed gun. Of course, once those plans are broadcast on the internet, enforcement is likely to be difficult. When Defense Distributed initially published its Liberator plans, Spain was the country with the most downloads — even more than the US.

Going Forward: Dealing With the Reality of DIY Weapons

A LEGO-like, single-shot plastic 3D-printed “Liberator” pistol isn’t going to turn the world upside-down by itself. But continuing advances in low-cost milling machines and 3D printers, along with advances in material science, mean that increasingly powerful weapons will be within the reach of many more people. Leaving aside the political question of whether that process should be regulated, as a practical matter, attempting to curb technology with legislation has always had a limited effect.

Some proposals call for making the plans, and even some of the needed components to create weapons, illegal. Perhaps the closest analog I can think of to that is the long-time federal ban on the sale of marijuana paraphernalia. While it has no doubt made consuming it a little more difficult, it certainly hasn’t done much to curb its use. In particular, the 3D printing industry is nervous about potential backlash and regulation that will impact the broad adoption of what is clearly an important emerging technology. A lot will depend on how the market for, and use of, DIY weapons expands, and how they are used.

Now read: PCMag’s Best 3D Printers of 2018