The term “ firearm” means (1) a shotgun having a barrel or barrels of less than 18 inches in length (2) a weapon made from a shotgun if such weapon as modified has an overall length of less than 26 inches or a barrel or barrels of less than 18 inches in length (3) a rifle having a barrel or barrels of less than 16 inches in length (4) a weapon made from a rifle if such weapon as modified has an overall length of less than 26 inches or a barrel or barrels of less than 16 inches in length (5) any other weapon, as defined in subsection (e) (6) a machinegun (7) any silencer (as defined in section 921 of title 18, United States Code) and (8) a destructive device.
