Not that I am about to buy one, but 3D printing has made massive
strides in the last couple of years. We are closely looking at the
technology for stuff other than the mockups and prototype parts
we have been making for more than a decade.
This is pretty impressive, although I bet there was final finish
work and that it likely has no rifling. Still - amazing.
http://www.youtube.com/watch?v=u7ZYKMBDm4M
Bill