I do "break in" my new rifle barrels, but not to the extent a lot of people do. I fire 5 rounds, clean, 5 rounds, clean, until I reach about 25 rounds. This is while I am sighting the rifle in, and doing initial chronographing of loads. When I clean the rifle after the 25 rounds, I clean with various solvents, then finish with JB Bore Shine which puts a little final polish on the bore. I normally only shoot heavy barrel rifles for Prairie Dog's, so I expect 1/4" or at least 1/2" accuracy at 100 yds.