I personally can't wait for the day that purchasing a 3D Printer is a realistic possibility for me, but I found this interesting and wondered what people's thoughts on this particular use of the device was.
A Working Assault Rifle Made With a 3-D Printer | Popular Science
Get ready. It's now possible to print weapons at home.
An amateur gunsmith, operating under the handle of "HaveBlue" (incidentally, "Have Blue" is the codename that was used for the prototype stealth fighter that became the Lockheed F-117), announced recently in online forums that he had successfully printed a serviceable .22 caliber pistol.
Despite predictions of disaster, the pistol worked. It successfully fired 200 rounds in testing.
HaveBlue then decided to push the limits of what was possible and print an AR-15 rifle. To do this, he downloaded plans for an AR-15 in the Solidworks file format from a site called CNCGunsmith.com. After some small modifications to the design, he fed about $30 of ABS plastic feedstock into his late-model Stratasys printer. The result was a functional AR-15 rifle. Early testing shows that it works, although it still has some minor feed and extraction problems to be worked out.