See this?  This is a gun partially manufactured with a 3D printer

A small company called Defense Distributed envisions a day when a freely-available weapon design can be relatively easily manufactured by anyone with access to a 3D printer. Make no mistake, 3D printer tech is going to get very advanced and reasonably inexpensive in the very near future. Then we'll see who gets to fire cool guns all the time, Mr. FPSRussia