If you can judge the distance to the tree or the position the the squirrel is in basicaly from your position horizontaly that is your range no matter how high the Squirrel might be in the tree, most misses up or down are from trying to allow for a longer shot than exists by the law of physics as gravity acts on the horizontal distance not the actual distance at the angle be it up or down.Basicaly the target is closer than it looks from the point of the bullets travel.