Very interesting topic. I don't see these as being a viable weapons system for some time if ever. People the world over have been making 'zip' guns from pipes, springs etc for a long time. Those lucky enough to have access to machine shops can make whatever they want. I don't see a widespread love of a plastic printed weapon at this time. Perhaps as tech evolves, but then, laws are sure to be enacted that prohibit three D printed weapons. This whole thing could blow up in the face of the RKBA community. If making your own gun is prohibited because of the fear of these new guns, one could forfeit the legal right to make a gun for themselves from any material/manufacturing process.
NRA Life Member