When Cody Wilson revealed the world’s first fully 3-D printed gun last year, he showed that the “maker” movement has enabled anyone to create a working, lethal firearm with a click in the privacy of his or her garage. Now he’s moved on to a new form of digital DIY gunsmithing. And this time the results aren’t made of plastic. Wilson’s latest radically libertarian project is a PC-connected milling machine he calls the Ghost Gunner. Like any computer-numerically-controlled (or CNC) mill, the one-foot-cubed black box uses a drill bit mounted on a head that moves in three dimensions to automatically carve digitally-modeled shapes into polymer, wood or aluminum. But this CNC mill, sold by Wilson’s organization known as Defense Distributed for $1,200, is designed to create one object in particular: the component of an AR-15 rifle known as its lower receiver. That simple chunk of metal has become the epicenter of a gun control firestorm. A lower receiver is the body of the gun that connects its stock, barrel, magazine and other parts. As such, it’s also the rifle’s most regulated element. Mill your own lower receiver at home, however, and you can order the rest of the parts from online gun shops, creating a semi-automatic weapon with no serial number, obtained with no background check, no waiting period or other regulatory hurdles. http://www.wired.com/2014/10/cody-wilson-ghost-gunner/
How is this different than the thousands of guys who have metal milling machines in their garage? Small ones, big ones, depending on their hobby and money. I personally know a guy who has everything he would need for this, as well as the stock, and drilling the barrel.
The difference is that this is a turn-key solution for creating the most difficult part of a specific gun. You don't have to already own a $5-$15k mill. You don't have to know how to convert an engineering drawing into a physical object. You don't have to know how to set up and align fixtures in a general purpose mill. You do still have to know how to assemble the other parts to an extent greater than most gun owners would routinely do, but this is a small hurdle. It makes the gun manufacture more like replacing brake pads and less like resurfacing brake rotors.
It also publicizes more widely (especially with the help of web sites like wired) the fact that it is actually possible to build your own gun. Many people consider any form of metal-working to be "professional" hard, and consider gun manufacture to require a level of precision far in excess of anything possible in a home workshop (at least partly because the set of gun enthusiasts and the set of home machining enthusiasts is rather disjoint). Gun manufacture is intimidating, and products/news like this reveals that to be not overblown