Many people have never heard of 3D printers. A 3D printer can print you a working Vice Grip tool, or about anything.
A guy has figured out the computer program for printing AR Lowers, Uppers, Magazines. He has also printed working handguns.
Check out this video. The Genie is out of the bottle now.
You can go to the web address shown on the video to download printable gun parts. All you need is a 3D printer, about twenty grand or so.