I remember the first time I heard about a fax machine. It was like something from a James Bond movie. Within a period of a few years, fax machines were everywhere. And a few years after that, they were common place.
3-D printers will be the same way.
Soon, everybody will have a 3-D printer. Sure, the government will try to legislate gun parts. If you’re caught with a magazine that holds more than X number of rounds, there will be repercussions. But that won’t stop a lot of people from printing and subsequently hiding combat-oriented gun parts “just in case.”
And this is a good thing, because in the case of a national emergency it will mean that more people will have the tools to keep their families safe and not have to suffer because Dumbo Joe Biden couldn’t understand “why you need” a 30 round magazine. Not to mention all of the other tools you’ll be able to print in the event of a less-than-total economic collapse but one that nonetheless affects distribution lines.