Also, you can really only 3d print the bottom half of a gun, the actual part that makes it a gun has to be made of metal and ordered online, then snapped on to the 3d printed plastic handle part.
The problem isn’t the plastic part you make at home… Literally, just make people print serial numbers on the important, metal part, and the whole problem goes away… But lazy journalists want to conjure images of people making anonymous guns at home cos it’s scary.