I've only been shooting my bow for about 8 months now. I use it only for hunting, mainly whitetail. Right now I'm comfortable out to 40 yards, but I've noticed something that's bugging me. Seems like my groups tend to spread from pretty tight at 15-20 yards to a horizontal line at 30-40 yards, getting more pronounced the farther back I go. I've been told that grip can cause this, but I'm very careful to not tightly grip the bow during the shot. Is there anything else form-wise that can cause this, or would I have to do some tuning to really fix the problem?