A gunmaker who calls himself Buck O’Fama (get it?) has posted an video of his 3D printed Ruger Charger receiver. This single part, which usually holds the serial number and is an integral part of the firing mechanism, is, technically, the only part that defines a weapon as an actual gun. By printing his (or her) own, O’Fama has essentially skirted the law that requires all firearms to be registered with the federal government. Unlike the 3D printed Liberator, this 3D-printed part requires very little structural support and is simply used to guide the mechanism while firing. In other...