There was a recent article on 3D printing in survivalblog.com. Decent article, with info to get you started, but not a lot of specific details. It included a link to a Deterrence Dispensed site with links to a whole host of 3D files, plus such things as the plans for building an AR lower out of sheet metal.
I suggest that even if you don't own a 3D printer, that you download everything that you MIGHT be interested in printing. The more the information is out there, the harder it is for them to stop it. The FGC-9 (F*%k Gun Control-9) uses 3D printing and hardware store parts, though it includes an AR fire control group. The AR fire control group (trigger, hammer, disconnector, along with springs and pins) is the one gun "part" to buy right away. Even a rifled barrel can be made at home, using electro chemical machining (ECM), which the FGC-9 instructions cover. ECM works fine with heat-treated steel, so you can buy a heat-treated steel "pipe" and turn it into a barrel.
I have
not tried this myself. I prefer to shop around at gunpartscorp.com and find a barrel that I can work with. I've been playing with sheet steel to see what I can come up with and haven't yet gotten into 3D printing. A "0%" receiver seems quite doable, either with 3D printed plastic, or with sheet metal, sorta' like
an AKM. You end up going down a rabbit hole with this kind of project, but it's an interesting trip!
