Section 16530 Of Division 2. Definitions From California Penal Code >> Division 2. >> Title 1. >> Part 6.

. (a) As used in this part, the terms "firearm capable of being concealed upon the person," "pistol," and "revolver" apply to and include any device designed to be used as a weapon, from which is expelled a projectile by the force of any explosion, or other form of combustion, and that has a barrel less than 16 inches in length. These terms also include any device that has a barrel 16 inches or more in length which is designed to be interchanged with a barrel less than 16 inches in length.
  (b) Nothing shall prevent a device defined as a "firearm capable of being concealed upon the person," "pistol," or "revolver" from also being found to be a short-barreled rifle or a short-barreled shotgun.