You can buy resin molds for the AR-15 lower, which is the regulated part. Then just buy all of the non-regulated parts retail and assemble a "ghost gun". There's also things like the FGC-9 which is mostly printed parts. And the Luty SMG if you're skilled enough.

This genie is so far out of the bottle, it's lapped the regulators and is going around again.

I honestly think those are better than the printed plastic versions in every use case except one.

Didn't some kid make a nuclear reactor in a shed

Yup.

But they want to control the pipeline all the same.

It should be totally possible to whittle a functional AR-15 lower. Especially if you wanted to mate it to one of those fancy new bufferless uppers, so you wouldn't even have to worry about the stock and buffer tube.

part of the problem with that is that most of your ghost guns are "just" the AR 15 lower receiver- the part classified as the "firearm" because of some technicality only a lawyer can understand.

It's not a load bearing, nor is it exposed to any particularly high levels of heat, nor any sort of particularly nasty gasses. So that can be printed in just about anything if the printer's resolution is good enough. (IIRC, they typically call for resin printers.)

Then, the ghost gun peeps just buy the rest of the components retail and pay cash.

for fully-printed firearms, you're looking at things like DMLS or other kinds of precision metalwork. It's the kind of work that would be more expensive than roadtripping to arizona and getting loophole-gun.

If they think making printers incapable of printing dicks, they’re going to be sorely disappointed when I show them what you can do with a photocopier.

Yep, it's bullshit. You're CNC/milling machine can actually make a firearm, a 3d printer cannon print a full firearm and requires outside and metal parts.