Every time you change targets you should rebuild your position no mater how small the change because you need to adjust the natural point of aim . If you can consistently put your shot on a 1 inch dot at 100 your gonna be GTG then move to 1/2 inch dots . A side effect will be your group size shrinking when checking zero . Doesn't make sense to me to practice shooting groups , especially at 100 , when the end goal is to place 1 shot on target at distance in field conditions . Group shooting is all well and good during load development but after that the ammo is better spent elsewhere working on precision instead of testing the accuracy of the rifle .