I was just talking over this exact topic with a friend that is a competitive benchrest shooter, gunsmith,machinist.
He said that he never shoots a competive 6ppc past 1200 rounds. he NEVER sets his B.R. barrels back just gets new ones. If they are for varmint use he stated that a barrel will last at least twice as long and setting the barrel back once is also an option if not for competition use.
UB
p.s.6br will have slightly less barrel life than 6ppc