ccoorreeyy.
Not a good idea. The fluting will release stress and enlarge the bore. Fluting needs to be done before riffling or the barrel has to be stress relieved before doing fluting.
Not too many gunsmiths have a stress relieve furnace. Doing fluting on a finished barrel could be a complete disaster unless the barrel is first treated.
On a Handi barrel hardly worth while. With a rebore job after fluting it can be done without stress relieving.
