Rev. Rul. 59-340, 1959-2 C.B. 375

      The Internal Revenue Service has had the occasion to examine
a weapon identified as the Unique, Model L, pistol and rifle
attachment.  The basic mechanism of the weapon is a .22 caliber,
semiautomatic, clip fed pistol.  The pistol barrel is readily
removable, and with the barrel removed, the mechanism will not
fire.  With the pistol barrel removed, the basic mechanism can be
inserted into a one piece rifle frame with a .22 caliber barrel
having a length of over 16 inches.

      Held, the Unique Model L, pistol and rifle attachment, a
combination pistol and rifle, is not a firearm within the purview
of the National Firearms Act (chapter 53 of the Internal Revenue
Code of 1954); however, it is subject to the Federal Firearms Act
(15 U.S.C. 901).

  Rev. Rul. 59-340