Defining loaded in California
"Loaded" from the Penal Code
12031. (a) (1) A person is guilty of carrying a loaded firearm when he or she carries a loaded firearm on his or her person or in a vehicle while in any public place or on any public street in an incorporated city or in any public place or on any public street in a prohibited area of unincorporated territory.
(e) In order to determine whether or not a firearm is loaded for the purpose of enforcing this section, peace officers are authorized to examine any firearm carried by anyone on his or her person or in a vehicle while in any public place or on any public street in an incorporated city or prohibited area of an unincorporated territory. Refusal to allow a peace officer to inspect a firearm pursuant to this section constitutes probable cause for arrest for violation of this section.
(f) As used in this section, "prohibited area" means any place where it is unlawful to discharge a weapon.
(g) A firearm shall be deemed to be loaded for the purposes of this section when there is an unexpended cartridge or shell in, or attached in any manner to, the firearm, including, but not limited to, in the firing chamber, magazine, or clip thereof attached to the firearm.
(h) Nothing in this section shall prevent any person engaged in any lawful business, including a nonprofit organization, or any officer, employee, or agent authorized by that person for lawful purposes connected with that business, from having a loaded firearm within the person's place of business, or any person in lawful possession of private property from having a loaded firearm on that property.
(j) (1) Nothing in this section is intended to preclude the carrying of any loaded firearm, under circumstances where it would otherwise be lawful, by a person who reasonably believes that the person or property of himself or herself or of another is in immediate, grave danger and that the carrying of the weapon is necessary for the preservation of that person or property. As used in this subdivision, "immediate" means the brief interval before and after the local law enforcement agency, when reasonably possible, has been notified of the danger and before the arrival of its assistance.
(k) Nothing in this section is intended to preclude the carrying of a loaded firearm by any person while engaged in the act of making or attempting to make a lawful arrest.
(l) Nothing in this section shall prevent any person from having a loaded weapon, if it is otherwise lawful, at his or her place of residence, including any temporary residence or campsite.
People v. Clark
People v. Clark specifically limited 12031(g) by holding that in order to be “loaded” a firearm must have ammunition “placed into a position from which it can be fired”. The case rested on the fact that a shotgun is not loaded when shotgun shells were attached to a shotgun inside a buttstock shell carrier.
There remains a lack of clarity whether a detachable magazine with rounds in the magazine inserted into the magazine well of a firearm is loaded as this may constitute a loaded firearm However, People v. Clark makes it very clear that loaded magazines in the same case or on a person's belt but not in the magazine well do not constitute a loaded firearm. Loaded magazines in a buttstock like the SU-16-CA but an empty chamber and magazine well would not constitute a loaded firearm.
There are uncommon exceptions in California law that state that a loaded magazine in the same area as an unloaded firearm constitutes a loaded firearm. Examples of those exceptions are in the course of committing a felony, carrying in the Governor's residence, and having been adjudicated a member of a criminal street gang. Those exceptions also help prove the rule that the definition of loaded firearm requires rounds in the chamber or rounds in a magazine in a firing position directly attached to the action.
Ammunition or Loaded Magazines in locked containers
There exists a myth in law enforcement circles that when complying with handgun transport restrictions, ammunition or loaded magazines can not be in the same locked container. As long as the rounds are not in the chamber and there is no magazine (fixed or detachable) with rounds in it that is directly attached in the firing position of the firearm, the firearm is considered unloaded. Please see Transport Restriction for Handguns for some important additional notes on transporting handguns in California.
The definition of "prohibited area" generally turns on whether the municipal or county code in that area prohibits the discharge of a firearm. Additional, Penal Code 374c makes shooting from any public road illegal.