Firearm
Firearm means any loaded or unloaded pistol, revolver, rifle, shotgun or other weapon which will or is designated to or may readily be converted to expel a projectile by the action of expanded gases, except that it does not include a pistol or rifle powered by compressed gas. The term firearm also includes irritant gas devices.
Source
36 CFR § 13.1
Scoping language
The following definitions shall apply to all regulations contained in this part: