I have never done anything special to break in a new barrel. I guess I use Vapos method. I clean the barrel before I use it then try to keep it fairly clean after that. I do not however let my barrels heat up much ever. I also tend to run my velocities quite bit lower that most reloaders. Accurate loads are much more important to me than velocity and as a rule, most loads are more accurate when reduced 5-8 percent from listed max. It is true that on rare occassions, max loads are more accurate. Usually not though. Depends on the powder and the nature of the beast.