I'd say shoot several fairly hard and fast bullets, maybe three at a time, clean in between each set, for maybe a box or two worth, then get the barrel hot by shooting a bunch through it. I may be totally wrong though, I don't really believe in barrel break in any way, hell, it's all heat treated metal. I know that people claim that it creates a solid bore so your accuracy remains constant, but if your bullets will effect the metal once, they'll do it easier next time, so I don't really believe in it, but if I did, that's how I'd do it, like a car motor, run it easy until it's set, then run it in.