The firearm receiver is the main part to which all other firearms parts are joined to form the completed, assembled firearm. The frame or receiver is the component that is regulated and can only be considered a firearm’s receiver once it has reached a stage of completion in which the threshold has been crossed to deem the item as readily restored or made to function. This matter is opined by an examiner who is experienced and credentialled in such questions in conjunction with determined guidelines. Therefore, companies that supply non-regulated components, receiver blanks, and accessories to non-licensed persons to self-manufacture provide the mostly completed but functionally incomplete blanks to the customer. The regulatory environment of parts and accessories has shifted, consider the recent example of triggers and stocks. Triggers were, at one time, unregulated parts until triggers of a particular design enabled a firearm to mimic fully-automatic firing. Trigger became regulated because of this feature, even though the part does not actually allow more than one round be discharged per single press of the trigger. The same is true for a certain styles of gun stock, which only became regulated on the introduction of stocks which offered functional equivalency of a fully automatic firearm. In either example, the function of the firearm was not in any way changed, these parts and accessories merely allowed the action to work more quickly while still functioning as a semi-automatic firearm, not as a machine gun.