Revenue Ruling 54-181

     Classification of certain weapons for determination of whether
     they are "firearms" within the meaning of that term as used in
     section 2733 of the Internal Revenue Code.

     Advice is requested whether the weapons listed below are
firearms under section 2733 of the Internal Revenue Code.
     Section 2733(a) of the code defines a firearm as "a shotgun or
rifle having a barrel of less than eighteen inches in length, or
any other weapon, except a pistol or revolver, from which a shot is
discharged by an explosive if such weapon is capable of being
concealed on the person, or a machine gun, and includes a muffler
or silencer for any firearm whether or not such firearm is included
within the foregoing definition, but does not include any rifle
which is within the foregoing provisions solely by reason of the
length of its barrel if the caliber os such rifle is .22 or smaller
and if its barrel is sixteen inches or more in length." 
     The following weapons, capable of being concealed on the
person, are firearms, being classified as "any other weapon":
       A U. S. Carbine M-1, .30 caliber semiautomatic, having an 18
     inch barrel with the stock sawed off leaving a pistol grip of
     four inches in length.
       A jackknife pistol.
       A palm-squeeze revolver.
       A single 18 1/2-inch barrel gun, chambered to fire 16 gauge
     shotgun shells, with sawed off stock, altered in such a manner
     as to change the characteristics of the original weapon so
     that it cannot be classified either as a shotgun or pistol in
     the commonly accepted definition of those words.
       A dipper percussion gun, which is made of bronze and which
     fires about a .32 caliber projectile by mean of a percussion
     cap, and is 13 1/2 inches overall in length, with a cup
     attached to one end.
       A gun made by using a .32-20 rifle barrel mounted on the
     receiver or frame of a .410 shotgun, with a pistol type grip
     at an angle to the bore for holding in one hand and designed
     to discharge a shot by the action of an explosive.
     The following weapons are not firearms within the meaning of
section 2733(a) of the Internal Revenue Code:
       A pistol grip type German Flare gun with two barrels 6 1/2
     inches in length which is not capable of firing shotgun
     shells.
       A twelve gauge, 30 inch double-barrel shotgun, one barrel of
     which has been sawed off to 14 1/4 inches.  Since the
     remaining barrel is 30 inches in length, the weapon is not
     considered capable of being concealed on the person.
     Section 2733(b) of the Internal Revenue Code defines a 
machine gun as "any other weapons which shoots, or is designed to
shoot, automatically or semiautomatically, more than one shot,
without manual reloading, by a single function of the trigger."
     An 8 millimeter caliber German Light Maxim Field Machine Gun
was altered by removing the original breech mechanism so that the
action and barrel assembly of a .22 short rim-fire autoloading
semiautomatic rifle, less wooden stock, forearm and sights, could
be cradled on the inside of the breech of the gun by use of
brackets.  Such gun was then capable of firing .22 caliber rim-fire
ammunition and is operated by means of a 110 volt switch-controlled
electric motor with a set of beveled gears to transmit motion of
the motor to the trigger mechanism of the rifle, so that when the
trigger of the gun is pulled, motion of the electric motor is
transmitted to the mechanism of the rifle, thus firing the gun as
long as the trigger is held back, or until the 15 shot tubular
magazine is emptied.  This weapon is classified as a "machine gun"
within the meaning of section 2733(b) of the Code.