Downvoted, why does everyone need to bring up the gun issue when somebody talks about the maker revolution? Big gun manufactures have been making guns for a long time. I don't see how people making themselves matters at all.
The point is the difficulty of enforcing gun control legislation, when a banned 30 round clip can be simply printed in anyone's garage from a easily transferred file. Not entirely germane to the present discussion I think, but not entirely irrelevant either.
"If reprap-like machines with strong materials turn out to be cheap and easy, then never mind licensing handguns — we're going to have a problem with home-made crew-served weapons." - Charles Stross
The drivers of new technology aren't always wholesome.