Falcon - You're missing the point on breaking in a barrel. The breaking in removes the fine burrs or other imperfections in the bore. Some bore are worse than others. The breaking in does not make a barrel shoot better (immediately). Barrel break in removes the barrel imperfections which can collect and hold fouling. It is the fouling that ruins accuracy. Breaking in allows you to clean the barrel better keeping it shooting good.
Breaking in will not make a lousy barrel shoot good no matter what.