Definition of a firearm/gun
Definition of a firearm
Knowing what is and is not a 'firearm' is important when mailing and transporting.
Generally, the serialized receiver or frame is considered a 'firearm'; everything else is just parts.
Despite the reference in California Penal Code, US Code has the definition in USC 921:
(a) As used in this chapter— ... (3) The term "firearm" means (A) any weapon (including a starter gun) which will or is designed to or may readily be converted to expel a projectile by the action of an explosive; (B) the frame or receiver of any such weapon; (C) any firearm muffler or firearm silencer; or (D) any destructive device. Such term does not include an antique firearm. ... (16) The term "antique firearm" means— (A) any firearm (including any firearm with a matchlock, flintlock, percussion cap, or similar type of ignition system) manufactured in or before 1898; or (B) any replica of any firearm described in subparagraph (A) if such replica— (i) is not designed or redesigned for using rimfire or conventional centerfire fixed ammunition, or (ii) uses rimfire or conventional centerfire fixed ammunition which is no longer manufactured in the United States and which is not readily available in the ordinary channels of commercial trade; or (C) any muzzle loading rifle, muzzle loading shotgun, or muzzle loading pistol, which is designed to use black powder, or a black powder substitute, and which cannot use fixed ammunition. For purposes of this subparagraph, the term "antique firearm" shall not include any weapon which incorporates a firearm frame or receiver, any firearm which is converted into a muzzle loading weapon, or any muzzle loading weapon which can be readily converted to fire fixed ammunition by replacing the barrel, bolt, breechblock, or any combination thereof.
(a) As used in this part, "firearm" means any device, designed to be used as a weapon, from which is expelled through a barrel, a projectile by the force of any explosion or other form of combustion. (b) As used in the following provisions, "firearm" includes the frame or receiver of the weapon ... (c) As used in the following provisions, "firearm" also includes any rocket, rocket propelled projectile launcher, or similar device containing any explosive or incendiary material whether or not the device is designed for emergency or distress signaling purposes ... (e) As used in Sections 34005 and 34010, "firearm" does not include a destructive device. (f) As used in Sections 17280 and 24680, "firearm" has the same meaning as in Section 922 of Title 18 of the United States Code. (g) As used in Sections 29010 to 29150, inclusive, "firearm" includes the unfinished frame or receiver of a weapon that can be readily converted to the functional condition of a finished frame or receiver.
Air guns are not firearms - no combustion.
Magazines are not firearms - no barrel.
Modern Tasers (1994 and later) are not firearms - no combustion; the original Tasers did use an explosive charge to launch the projectiles.
California antique firearms
16170. (a) As used in Sections 30515 and 30530, "antique firearm" means any firearm manufactured before January 1, 1899. (b) As used in Section 16520, Section 16650, subdivision (a) of Section 23630, paragraph (1) of subdivision (b) of Section 27505, and subdivision (a) of Section 31615, "antique firearm" has the same meaning as in Section 921(a)(16) of Title 18 of the United States Code. (c) As used in Section 17700, "antique firearm" means either of the following: (1) Any firearm not designed or redesigned for using rimfire or conventional center fire ignition with fixed ammunition and manufactured in or before 1898. This includes any matchlock, flintlock, percussion cap, or similar type of ignition system or replica thereof, whether actually manufactured before or after the year 1898. (2) Any firearm using fixed ammunition manufactured in or before 1898, for which ammunition is no longer manufactured in the United States and is not readily available in the ordinary channels of commercial trade. 16180. As used in this part, "antique rifle" means a firearm conforming to the definition of an "antique firearm" in Section 479.11 of Title 27 of the Code of Federal Regulations.
But for purposes of transport and concealed carry, and in the commission of crimes, antique firearms are firearms.
Because of the definition of firearm, a firearm disassembled into a collection of parts is still a firearm. That the weapon cannot be fired is not relevant.