In the “Liberator” model publicized last week, the ONLY metal part is the firing pin (needed the hardness to dent the primer sufficiently. The springs are a pair of circular springs (think a clock or wind up toy guts) made on the 3D printer. Apparently the barrel is just plastic from the printer.
Certainly not a durable or even desirable, or useful firearm. But, if it can fire a bullet with the force from an explosion it qualifies as a firearm, and will be treated as such. Of course the usual suspects will immediately predict mayhem and blood in the streets and demand they be banned along with any other types of guns that have any plastic in them.
The first automobiles were not very sophisticated either, but matured rapidly become pretty handy items. The 3D printer technology may eventually mature and make practice guns. I predict they could also “print” shootable bullets and even cartridge cases within a few years
Of course all they hysteria over a marginally functional 3-D printer gun ignores the fact that someone with a bit of tubing or pipe the right size and a few pieces of scrap metal can make a deadly “zip gun.” Or that “STEN” type submachine guns can be made with very primitive tools, and a muzzle loading gun can be made with little more than a hammer, anvil, hand drill and some files.