in trad archery it is always helectical. we don't use drop away rests either the arrow sits on a solid wedge of leather and they come off cleanly. uit starts the shaft spinnign, that kills archjers paradox and gets it goin on a straiter trajetory, like a rifled barrel or a flatbore musket, the rifled one shoots straiter. and when hunting it gets the broad head to cause more damage by rotateing thru the target like a sawblade cutting a nice big hole.