Put simply, producing a 3D printed gun is akin to making a ladder from dried pasta. It IS possible but totally impractical. There are very affordable, easily available machinery and parts from retailers such as B&Q that could contribute to the manufacture of a firearm far more efficiently.
3D printers are coming to Britain. This autumn Selfridges is offering a London-based printing workshop, allowing people to make 3D-printed statuettes of themselves. It's all very exciting, but - like most technology - it has a dark side too and has the potential to kill.