3D printed guns....

Yesterday, I wrote about Defense Distributed's 3D printed handgun, and asked whether it would fire, and how many rounds it could fire before experiencing stress fractures, melting, etc. Now, Forbes's Andy Greenberg follows up with a report of the successful firing of the gun -- though not its longevity -- and says that Defense Distributed will publish the CAD files for printing your own gun on its site today, along with videos of the gun in action.

Unlike the original, steel Liberator, though, Wilson’s weapon is almost entirely plastic: Fifteen of its 16 pieces have been created inside an $8,000 second-hand Stratasys Dimension SST 3D printer, a machine that lays down threads of melted polymer that add up to precisely-shaped solid objects just as easily as a traditional printer lays ink on a page. The only non-printed piece is a common hardware store nail used as its firing pin... Even Wilson himself says he’s not sure exactly how that’s possible. But one important trick may be the group’s added step of treating the gun’s barrel in a jar of acetone vaporized with a pan of water and a camp stove, a process that chemically melts its surface slightly and smooths the bore to avoid friction. The Dimension printer Defense Distributed used also keeps its print chamber heated to 167 degrees Fahrenheit, a method patented by Stratasys that improves the parts’ resiliency.