What you're looking at above is the "Lulz Liberator", a fully-functional $25 handgun that was made with a Lulzbot 3D printer. It fired 9 shots successfully, with one plastic barrel surviving eight shots - another barrel was swapped in for the ninth. Continue reading for a video and more information.
Just how the Lulz Liberator survived those explosions isn't exactly clear. Joe claims that the plastic he used, the generic Polylac PA-747 ABS fed into most consumer 3D printers, is actually stronger than the more expensive ABS plastic used in a Stratasys printer. In fact, before using a Lulzbot-printed barrel, he and Guslick tested one made on Guslick's Stratasys printer. That barrel exploded on firing, though Joe blames the problem in part on its having been printed with a smaller chamber, the space at the back of the barrel into which the round is inserted.