I haven't had my bore scope for very long at all. Recently, I barrel up a 22 creedmoor criterion. I bore scoped it new & unfired. I just put the first round down the barrel and after bore scoping again was a bit surprised at how very little copper fouling there was. Mostly surprised in the lands that there was none. I'm going to go ahead and clean it anyway. I really thought there was going to be a little bit of copper there where the reamer cut the lands.