I would agree with the MIKE. You could be torquing your wrist or locking your elbow out or changing your form just slighting giving the changes in your grouping on the target. Get you a kisser button and tuck it in the corner of your lip for a consitent anchor point and when you are at full draw you should be able to relax the hand holding the bow with then your thumb and pointer finger. Squeeze the trigger while holding on your target to get the "suprise release". Take notice of your stance, form, and anchor point. Takes alot of practice but youll get there. When I firsted started shooting this would happen to me as well. I didn thave kisser button and I would either putting my eye forward closer to the peep or farther away and that cause me to shoot little higher or lower but with good grouping. Hope this helps. Practice Practice Practice and get kisser button.