I used to use the G. David Tubb method. I figured if anyone had figured out how to break in a barrel it would be him. So I bought two R-15's when they came out and broke one in that way, and then shot the other one at paper before I broke it in. It made a teeny tiny difference was all. The difference in aggregate of five, five shot groups with each rifle was .092". Either rifle will smack a coyote if I do my part. The coyotes don't seem to know the difference either.
Personally, I don't think it's worth the time and effort unless you plan on shooting F-class or some other competition like that where a little tiny difference in your group size will mean a trip to the prize table or not. Doubt that I will do it again, until I build my "dream" rifle.