As remarkable as the process is, considering the cost of the printer and the materials that go into the gun, and the inherent short lifetime (until they figure out how to incorporate a powdered ceramic ink for the barrel), it'll be a lot less expensive to just go to the gun shop (or show) and pick up a pistol or two or twenty...
"Defcad is experiencing heavy traffic at the moment. Please bear with us."......three thousand hits per hour.
It was downloaded over a thousand times before the Department of Defense pulled it. The Pirate Bay is now hosting a link to the torrent. isohunt and kickass torrents also appear to have links. It will be very difficult to legislate this out of existence, but it will be amusing to watch them try.
Very few people would have any interest in a one shot firearm, but as technology advances and materials evolve who knows what it could turn into. Perhaps a government nightmare.