Once you get to the point you have to quit shooting groups because to are damaging your arrows you are getting there....
but amazingly enough you don't get there by shooting groups at all. Much better to have multiple dots on your target.... aim small, miss small
When shooting groups, you can't help focusing on your arrow knocks already in the target, and subconsciously you are adjusting your aiming point with each shot. Shooting 5 different spots on an NFAA 300 round is good, or 3 different spots on a 300 Vegas round will sharpen up your game indoors.... but when shooting a 3D target its best to shoot one arrow at a time & pull it.... THAT is good hunting practice.