Published at LiveLeak by Buck O'Fama (just possibly a pseudonym) is this video demonstration of a 3D-printed pistol version of a Ruger 10/22—a popular semiautomatic .22 rifle. The receiver is 3D printed and glued together, with metal parts added, including what appears to be the bolt (and, I assume, a synthetic after-market stock*).
The text reads:
The pistol version of the popular Ruger 10/22 rifle, the Ruger Charger comes standard with 10-round flush magazines and can accept high-capacity mags holding 30 rounds or more. As demonstrated, making one with a cheap small-format 3D printer and some parts purchased on the internet (with no paperwork) is trivially easy.
We don't see the printing process, so we'll have to take Buck O'Fama's word that the Ruger Charger was "printed in two sections on an inexpensive, small-format 3D printer, and those sections were crazy-glued together," and joined with mail order parts. But this seems a logical development of the 3D-printed firearms technology that we've seen evolve over the last year-plus.
Solid Concepts, an engineering firm, has fully 3D printed metal 1911-style pistols on high-end printers, but this is the closest we've come so far—and damned close it is, if this pans out—to a 3D-printed semiautomatice firearm being produced on an inexpensive machine.
O'Fama closes closes the video by pointing out, "If you take my gun, I will simply print another one."
*Commenter MegaloMonocle says that's a wood stock, not synthetic.