From what Ive been told, the rifling in a new barrel is microscopically burred and will embed w/ copper fouling ,that may never come clean and affect accuracy, if not removed after each shot. I shoot ten rounds cleaning after every shot, then every 3 shots till about 40 rnds then I clean it really good when I get home w/ "truly magnificent" bore solvent until there is absoultly no visible copper residue in the barrel.