Long, not toooooo long story. Thirty years ago I was friends with Carl Hildebrandt who ran the the R&D at Savage. H&R had filed bankruptcy and was selling off their machinery; and Carl got Ron Coburn (CEO) to go to the sale with him. As Carl tells me, this odd-looking piece of machinery came up. Carl tells Ron. "Buy me that!". He would not tell him why or what it was for, but got the tooling bought. About two (?) weeks later, he calls him down to the shop. Carl has a barreled action set up in a jig he had fashioned. As Ron watches, Carl indicates the machine on the barrel, and starts it up. It proceeds to slowly mill six equally spaced cutters down the barrel, and back up. Half the depth down, and the other half on the way back to the receiver end.
The tooling was used by H&R to simultaneously cut six flutes at 60-degree intervals on their revolvers. Carl figured out that cutting all six at once, using hydraulic pressure to equal the stresses would not "bend" the barrel, as cutting them one at a time might. Carl had tested the process on a couple dozen barreled actions beforehand. He would have the employees fitting barrels to actions, send him several each day. He clamped the barreled action in a sort-of Railgun, and tested them for accuracy. He would then flute each one, and retest. He told me that about 85% of the barrels fluted shot more consistently (accuracy), the rest accuracy level did not degrade. His conclusion was that their system did not hurt, but usually increased both absolutely accuracy, and made the groups more rounded, with fewer fliers. It seems logical...
So, that is what I know, VS what I think.
As far as Shilen voiding the warranty if you flute, one spring afternoon I was sitting under the awning of Ed's motorhome, someone asked Ed about fluting. Ed replied that the warranty was voided if you did so. Tony Boyer then told the assembled multitudes that Ed shipped him six LV and six HV barrels each year. He had his gunsmith flute them, with the barrel fit, chambered, and headspaced to the action. Ed just sort-of sat there...