On my 270 AM, when the throat went to pot I used the complete final finish process. Immediately restored accuracy. . . for about 50 shots.
The first couple of inches of rifling are simply not there. She was rode hard and put up wet for about 900 rounds.
On my 338 RUM which started out as a 338 Win Mag (got a $40.00 unfired 338 RUM take off barrel from Kirby) I ran half of the FF bullets through it in the proper. However, I did not use the most course bullets.
My only regret is that I was impatient enough to not shoot some loads prior to the FF process.
The rifle shoots as good as the ones I got from Kirby. After 20 or so shots an overnight Wipeout and 3 patches she's clean. Only a slight blue color on the first patch.
I've followed the first patch with Warthog II to validate copper removal. The Wipeout got it all.
There are those that use only the finer FF bullets even on new hand lapped barrels.
I wouldn't hesitate to give it a go but wouldn't use the coarsest set of bullets. They say that only 0.0004" are removed with the full meal deal, if I remember right. I have no way of verifying that.
BTW, the best bullet all the way around for that thing has gotta be the 300 Berger.