Rev. Rul. 56-234

The Internal Revenue Service has been requested to classify a choke, known as a `Flex-Choke,' for purposes of the requirements of the Federal Firearms Act, that is, whether a person engaged in the business of manufacturing such choke must be licensed to transport, ship, or receive the device in interstate or foreign commerce.

Section 1(3) of the Federal Firearms Act, 15 U.S.C. 901(3), provides as follows:

The term `firearm' means any weapon, by whatever name known, which is designed to expel a projectile or projectiles by the action of an explosive and a firearm muffler or firearm silencer, or any part or parts of such weapon.

For the purposes of the above statute, any component, part, or appurtenance which affects the basic function of a weapon is considered in the category of a `part' thereof. Accordingly, as the choke in question is designed to be affixed to the muzzle end of the barrel of a shotgun for the purpose of controlling the pattern of discharge from such weapon, it is a firearm within the purview of the Federal Firearms Act. A manufacturer of, or a dealer in, a shotgun choke must be properly licensed under the Act to lawfully transport, ship, or receive the device in interstate or foreign commerce and must also otherwise comply with the law and regulations.