As used in this chapter, the following terms shall have the meanings indicated:
Any instrument used in the propulsion of pellets, shot, shells or bullets by action of gunpowder, compressed air or gas exploded or released within it, and includes any weapon commonly referred to as a "pistol," "revolver," "rifle," "gun," "machine gun," or "shotgun." Any weapon that can be made into a firearm by the insertion of a firing pin, or other similar thing, or by repair, is a firearm.