For this exact reason right here I wish they would change that to be CBTO instead of COAL.When you say bullet length, do you mean the projectile length, or cartridge over al length? I never change the bullet length to something different than what the bullet file suggests. If you do measure your bullet lengths chances are you will find surprising variances with hollow points, even Berger match bullets. Ballistic tips are probably better, but I would go with the suggested lengths in the file.