I just read an article in a Guns magazine, 3 year old issue on breaking in a new barrel about 20 minutes ago. The writer basically claimed that this process of shooting a round, then cleaning, then repeating this process for 10 shots is a waste of time, and wont help much at all. He went on to state how many shooters think they can turn an off the shelf rifle into the category of a custom rifle by this process. There is no way you can turn a 5moa shooter into a 1 moa shooter with this process. Brass, copper, and lead are not hard enough to polish a steel barrel. I'm far from an expert, but ya, I agree that a bullet is not hard enough to have an affect on steel, other than leaving behind a deposit.