Parts are not a firearms. It's a mechanical item, just like a vehicle. Stuff wears out, or you buy parts to make it more user-friendly.
No, the atf doesn't get to make rules, only supposed to enforce the law enacted by congress.
https://www.wnd.com/2023/11/2a-victory-federal-appeals-court-strikes-biden-atf-ghost-gun-limits-rules-agencies-cannot-write-laws/
