An 80% lower is a paper weight.
Once it's build out, the configuration in which it is first assembled dictates what it is.
If you first assemble it as a pistol, it's a pistol.
If you first assemble it as a rifle, it's a rifle.
Same thing applies to any stripped lower that's purchases as a "receiver".
I know this is an old thread but you are incorrect. An UNREGISTERED fire arm is anything you want it to be. Thats the point of an UNREGISTERED fire arm. So long as what ever you build is legal for you to own you are just fine. If you have a lower with a serial number, then its either registered as a pistol or a rifle
