Quote Originally Posted by Martinjmpr View Post
I'm pretty sure that's not how it works. The 80% refers to the lower receiver, nothing else.

It doesn't matter what else you include, the only part that is considered a "firearm" under applicable Federal laws is the lower so whether you include an upper, stock, etc is irrelevant.

My guess is that Polymer is selling "80% receivers" PLUS all the parts to finish that 80% into a finished receiver (jigs, drill bits, templates, etc.) THAT is what makes it a firearm in the eyes of the ATF.

Is it weak? Maybe, maybe not but agency "interpretations" are given wide latitude by courts.
It’s soy only diet levels of weak. It’s simply not a firearm. And no amount of tutorials, equipment, etc. make it so.