Source : Webster's Revised Unabridged Dictionary (1913)

Rifling \Ri"fling\, n.
   (a) The act or process of making the grooves in a rifled
       cannon or gun barrel.
   (b) The system of grooves in a rifled gun barrel or cannon.

   {Shunt rifling}, rifling for cannon, in which one side of the
      groove is made deeper than the other, to facilitate
      loading with shot having projections which enter by the
      deeper part of the grooves.