Some people have their backs up over plans being available on the internet for 3D printing firearms. To be blunt, I have some knowledge therewith, and these people are speaking from ignorance. Unless they are not... and then they are lying.
It's always been completely legal for a person to build themselves a firearm. Owning it legally may depend on location, and certainly certain conditions regarding prohibited persons. This 3D technology does not alter any of that, except to introduce a particularly expensive and poor quality way of doing so.
Last weekend, 64 people were shot in Chicago, and 12 of them died. All in one of the most heavily restricted firearms ownership cities in the United States. Ooops.... latest count makes that 71 people shot. In two days. In a city where no one (only law abiding citizens need apply) is allowed to buy or own a handgun.
NOT one of those criminal acts was done with a home made weapon, let alone a single shot rimfire the size of a toaster that had been 'printed' with $3K in equipment.
Allow me to throw a wrench into the discussion of Orwellineese shutting down knowledge because some few people have panty-bunched over it. Do you know who is the single largest distributor of free firearms design plans in the entire world? Yup.... that's right Sparky.... the United States Federal government. It's called the US patent office, and every weapon design for the last 100 years is there for the asking.
One of those plans, and an Afghan Immigrant from the Kyber Pass armed with a coal forge and some home made hand tools can build you any number of squad automatic weapons. You too can be laying down suppression fire in only a few weeks!