As used in this section, "firearm" shall mean any
handgun, rifle, shotgun, machine gun, automatic or semiautomatic rifle,
or any gun, device or instrument in the nature of a weapon from which
may be fired or ejected any solid projectable ball, slug, pellet,
missile or bullet, or any gas, vapor or other noxious thing, by means
of a cartridge or shell or by the action of an explosive or the igniting
of flammable or explosive substances. It shall also include, without
limitation, any firearm which is in the nature of an air gun, spring
gun or pistol or other weapon of a similar nature in which the propelling
force is a spring, elastic band, carbon dioxide, compressed or other
gas or vapor, air or compressed air, or is ignited by compressed air,
and ejecting a bullet or missile smaller than 3/8 of an inch in diameter,
with sufficient force to injure a person.