Most people have no idea just how simple an item that a gun can be. In WWll, the Germans developed a family of small arms that could be produced in basement workshops for their “last stand” that, fortunately, never came about. I’ve seen a few examples that were brought back; crude, yes, workable, very much so. I am still dubious about guns produced with 3-D technology because, for reliability and accuracy reasons, some parts really do need to be made of metal. But, for those who have long dreamed of disarming the American people, this is proof that they have sorelyunderestimated our ingenuity and resourcefulness. My big concern is something like DHS trying a heavy-handed crackdown that would spark a second American civil war.
Today... They need to be made of metal. Future changes in materials science could radically change that.