This has been asked before and the general concensus is that it is inadvisable. Not only can the barrel be weakened, but fluting can affect the barrel stresses and the result will be inaccuracy. Sometimes things work out fine, but if they don't you can have a ruined barrel, or worse.
Someone asked how you would know if the cuts were too deep. My response was that you found out when the barrel split, maybe took the receiver ring along for the ride, and your eyes, fingers, or other parts of your anatomy departed. Then you know what not to do the next time.
Jim