What Bronko 22000 said!! Go to Dan Lilja'a web site. He is both a gunsmith and now better know for being a barrel maker. If you look through his site you'll see the break in process he recomends. It's time consuming but he doesn't make any money on reloading components so it must be the gospal. Most all barrel Manufactures recommend a "Break-in" Procedure. You'll probably find in most factory barrels it isn't worth the time. There pretty rough. In custom barrel I would follow their recommendation. Of course until you have a custom barrel chambered you'll have as much in the barrel as you have in most of the shelf hunting rifles.