The pressure-bearing components usually aren’t 3D-printed, but it turns out those aren’t hard to make from innocuous stuff found at any hardware store (or if you’re in America just buy “spare parts” lmao).
I was under the impression that only receivers were actually regulated in the US ? So yeah, if you can print a receiver you should be able to legally buy the rest of the gun as spare parts
Printing is probably easier but is actually unnecessary.
https://web.archive.org/web/20241211151625/https://www.80-lower.com/80-handgun-frames/
I’m pretty sure that if you order from this website you get put on a list, but if you don’t have a 3D printer, a few minutes with a Dremel is all you really need.