I think the printing technology will affect gun control. Remember, in primitive countries people have long made their own firearms by hand. I have seen films of 1911s being made, one piece at a time, by hand in Afghanistan and else where.
Videos are starting to go around showing how to make guns in a simple home shop. And, those with milling machines, lathes, etc. could make almost anything.
I made zip guns from junk piles in Chicago when I was a youngster.