I have a "friend" who wants to build an AR15 from an 80% receiver, but (s)he's a bit of a noob and has asked me to help out. If milling an 80% lower turns it into a firearm, then installing the FCG and buffer assembly shouldn't make it any extra firearm-y, so I should be okay doing the assembly after my friend has done the milling, right? I just want to stay on the right side of regs for finishing an 80%, especially since the new rules will be rolling out soon.
