Those Controversial 3D-Printed Guns, Explained No, you can’t just download a gun from the Internet. Here's what's really going on.

Those Controversial 3D-Printed Guns, Explained No, you can’t just download a gun from the Internet. Here's what's really going on.
A legal agreement between the U.S. government and a gun rights organization is setting the stage for the latest skirmish in the wars over gun rights and gun control. The agreement allows the group Defense Distributed to host a collection of files online that can be downloaded and, with the help of a 3D printer, can print the necessaryparts to build working firearms.
Numerous states are now rushing to ban their residents from downloading the files. Even the President of the United States weighed in. But the truth here is a little murkier than the headlines. What a Gun Is Here's the first thing you need to know: These files are the instructions sets for 3D printing items that are legally considered firearms. But in reality, what they add up to falls far short of an actual, workable gun.

When most people think of the word "firearms," they picture complete rifles, shotguns, pistols, and revolvers. Load them with ammunition, pull the trigger, and they fire. But there’s another definition of "firearm."
Rather than just buying a whole weapon at a gun store, many gun enthusiasts like to build their guns from the ground up from a collection of parts. Of course, the government must regulate these homemade guns, which is why it classifies their receivers—basically the frame that holds the key parts—as a type of firearm. After all, without the frame you can’t build your firearm.

Defense Distributed’s controversial files are designed to 3D-print receivers. What comes out of the 3D printer isn't a working weapon, but something that still must be mated to bolts, barrels, trigger groups, stocks, and other necessary parts before it ever fires a bullet. Defense Distributed’s Liberator pistol design is perhaps the closest thing to a complete printable firearm, but the enthusiast must still source key parts such as a metal tube for a barrel and a nail for a firing pin.
The First Amendment vs. the Second The U.S. government recognizes the right of citizens to build their own firearms, and all of these parts are readily available in gun shops or online, as they always have been. So all of this is perfectly legal. Where Defense Distributed and the government clashed is over the ability of people in foreign countries to download the files.
For example, the government’s International Traffic in Arms Regulations (ITAR) statute prohibits the transfer of weapons technology abroad without express permission. Hosting the files online allows anyone around the world to download them—a no-no under ITAR.
Defense Distributed, on the other hand, claimed that the government violated the First Amendment by preventing them from uploading the files. The State Department, which oversees arms exports, has now decided that the files are exempt from ITAR. Defense Distributed is free to share the files online.
The agreement has gun control groups and state and local officials up in arms. “The federal government is trying to allow access to online plans that will allow anyone to anonymously build their own downloadable, untraceable, and undetectable gun,” Massachusetts Attorney General Maura Healey wrotein a letter to U.S. Attorney General Jeff Sessions.

The state of Pennsylvania won a temporary agreement from Defense Distributed to prevent its citizens from downloading the files. The head of the Brady Campaign called the State Department’s decision “bitterly disappointing.” President Trump himself entered the fray, muddying the waters with his own misunderstanding of the issue. (The receivers are neither for sale nor are the resulting guns entirely made of plastic.)
The Fourth-Easiest Way To Get a Gun? Receivers like those in the Defense Distributed case are freely available right now on the open market—and unregulated—because they are “80 percent parts.” That is to say they are about 80 percent of a working firearm, requiring a person to have only a drill press or hand tools, and the requisite DIY skills, to finish the remaining 20 percent.

Building a gun this way from parts already on the market is much easier and cheaper than the new and controversial 3D printing method. I once did it in my own kitchen, and the result is a much more reliable, durable firearm than you'd get from 3D-printed parts. Frankly, 3D printing gun parts is the most complicated way for a criminal to get his hands on a firearm, after stealing a gun from a legal gun owner, buying a gun on the black market, and finishing an 80 percent receiver.
We should absolutely be careful about anything that makes it easier and quicker for people to get their hands on guns. We don't know whether Defense Distributed's file sharing will lead to a meaningful bump in 3D-printed gun crimes, but criminals smart enough to 3D print their own guns are also smart enough to see the shortcomings in the process and find another way to get them. Despite all the fire and fury of the past week, over the long term it’s likely the files will be much more useful to tinkerers and hobbyists operating within the law.

https://www.popularmechanics.com/military/weapons/a22604405/3d-printed-guns/