Downloading a gun's design plans to your computer, building it on a three-dimensional printer and firing it minutes later. No background checks, no questions asked.
Sound far-fetched? It's not. And that is disquieting for U.S. gun control advocates.
At least one group, called Defence Distributed, is claiming to have created downloadable weapon parts that can be built using the increasingly popular new generation of printer that uses plastics and other materials to create 3-D objects with moving parts.