Im not going to get into a debate. But if you follow ATF guidelines and regulations only the receiver of a firearm is considered a firearm. Hence why you can buy any part of a firearm ex. Slides, barrel, mag release. Bolt parts for rifles, stocks. Etc... But you cannot buy any type of receiver without an ffl. And I agree with you aswell I would not feel comfortable sending any part of my firearm to a random person without credentials.