I’m in favor of sensible gun-control regulations, but soon enough controlling guns will be an antique idea. My initial reaction to 3-D printers was that they’ll be used to make untraceable firearms (or, worse, biological weapons), especially when it’s easy for a 3-D printer to make other 3-D printers which will make other 3-D printers. A scary parallel to our concerns about government intruding more in our lives with technology is that many dangerous things in our decentralized world are becoming beyond its reach.

The 3-D printer is still in its crude stage, but Andy Greenberg has written an article about using a Ghost Gunner machine to make an untraceable AR-15 in his office at Wired. The opening:

THIS IS MY ghost gun. To quote the rifleman’s creed, there are many like it, but this one is mine. It’s called a “ghost gun”—a term popularized by gun control advocates but increasingly adopted by gun lovers too—because it’s an untraceable semiautomatic rifle with no serial number, existing beyond law enforcement’s knowledge and control. And if I feel a strangely personal connection to this lethal, libertarian weapon, it’s because I made it myself, in a back room of Wired’s downtown San Francisco office on a cloudy afternoon.

I did this mostly alone. I have virtually no technical understanding of firearms and a Cro-Magnon man’s mastery of power tools. Still, I made a fully metal, functional, and accurate AR-15. To be specific, I made the rifle’s lower receiver; that’s the body of the gun, the only part that US law defines and regulates as a “firearm.” All I needed for my entirely legal DIY gunsmithing project was about six hours, a 12-year-old’s understanding of computer software, an $80 chunk of aluminum, and a nearly featureless black 1-cubic-foot desktop milling machine called the Ghost Gunner.

The Ghost Gunner is a $1,500 computer-numerical-controlled (CNC) mill sold by Defense Distributed, the gun access advocacy group that gained notoriety in 2012 and 2013 when it began creating 3-D-printed gun parts and the Liberator, the world’s first fully 3-D-printed pistol. While the political controversy surrounding the notion of a lethal plastic weapon that anyone can download and print has waxed and waned, Defense Distributed’s DIY gun-making has advanced from plastic to metal.•