I am still waiting on a good, logical, explanation on "why break it in" from the break it in camp.
A very good mate of mine who shoots out to 1200 yards (silver medallist at 1000, 1100 and 1200 yards this summer at Bisley) swears by it. Mind you he puts lots more down his competition barrels than I do and he believes it gets him about 1/3 more rounds life out of the barrel!