There's a few more links inside the following stories. Pretty amazing stuff.
HaveBlue reportedly used a Stratasys 3D printer to craft the part, assembled it as a .22 pistol and fired more than 200 rounds with it.
The tester then attempted to assemble a rifle with the part and a .223 upper receiver but had “feed and extraction issues.” The problem may not in fact be with the 3D-printed part, though, as the issues remained when a standard aluminum lower was used.
3D printed AR -15
Second link doesn't work, is it supposed to go to ?
links don't work
So he printed a lower receiver (the most important part) and bough the rest of the stuff from a gun store, Still a cool idea. I am sure there would be 3D print schematics for less complex firearms. Like this thing that the allies gave to the French resistance in WWII http://en.wikipedia.org/wiki/FP-45_Liberator
It's only one part. I still remember the drama that happened on thingiverse about the 3d printable weapon parts/attachments.
Although we have the technology to print an entire working gun, it's still out of reach for most people.
Anyway, here's a 3d printable nerf gun