Pen Guns Classified s Firearms

     The Bureau has held that a small caliber weapon ostensibly
designed to expel only tear gas, similar substances or pyrotechnic
signals by the action of an explosive, which may readily be
converted to expel a projectile by means of an explosive,
constitutes  "firearm" within the purview of 18 U.S.C.
921(a)(3)(A).

     The Bureau has long held that such weapons when actually
converted to fire other than the gas or pyrotechnic cartridges
originally designed for use therewith are "firearms" under Chapter
44 an the National Firearms Act, depending on the individual
characteristics of the weapon.  See Revenue Ruling 56-29, supra,
and Revenue Ruling 56-597, C.B. 1956-2, p. 931 (Internal Revenue).
These determinations with respect to the converted weapon were not
altered by the amended definition of the term "firearm" now found
in 18 U.S.C. 921(a)(3)(A) and the term "any other weapon" in 26
U.S.C. 5845(e).  Accordingly, any such weapon which is capable of
being concealed on the person which has originally been designed or
converted to discharge a shot through the energy of an explosive
will remain subject to the provisions of the National Firearms ct
as an "any other weapon" (26 U.S.C. 5845(e)).

     Such weapons manufactured within the United States on or after
June 1, 1975, re subject to all of the provisions of Chapter 44 and
26 CFR Part 178.  Such weapons manufactured before June 1, 1975,
and which may still be in inventory, are exempt.

     Revenue Ruling 56-29, C.B. 1956-1, p. 552 (Internal Revenue),
is hereby revoked.  ATF Ruling 75-7, ATF C.B. 1975, p. 55.