Try this. Put a small dot at the top of your target. Then, tape a strait line down the lenth of the target. Shoot a group with the 20 yd pin at the dot.Assuming it groupedon the dot,then shoot a group from 30 YARDS USING YOUR 20 YARD pin again. Shoot another group from 40 yards USING YOUR 20 YARD pin again. If all groups are notON the line progressively lower down the target, you have a tuning issue with the rest and it will need to be moved side to side. ie: if the groups wander farther and farther from the line from the farther distances you need to adjust the rest.