Rev. Rul. 55-358

Section 1(3) of the Federal Firearms Act, 15 U.S.C. 901(3), defines a firearm as 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. Held, a pistol or revolver grip, whether of standard or custom design, is a component part of a firearm, as distinguished from accessories or attachments thereto, and therefore is a `firearm' within the purview of section 1(3) of the Act. While a dealer, defined in section 1(5) of the Act, 15 U.S.C. 901(5), may manufacture special stocks, etc., a license as a manufacturer is required to lawfully engage in the manufacture or importation of pistol or revolver grips in quantity lots for purposes of sale or distribution