Best way to tell is if possible would be to set target at 125 yds and aim at center and see where your group hits. After that back target to 150 yds and shoot a group still aiming at the center of target. Keep moving target back 25 yds til you get back to around 225 yds. By aiming at the center your groups will be dropping below the center of target and give you better idea of where your groups are hitting at various yardage.