The notion firearms are complicated and difficult to make persists...Yet people in 3rd World countries make all sorts of small arms with little more than hand tools...And often do some very nice work in the process...
https://www.youtube.com/watch?v=FinRqCocwGE
The link for Free 3D printable gun blueprints is:
www.codeisfreespeech.com
I have no printer, but I downloaded all 10 to show support for the First Amendment