The above mentioned setup works, howeverit has been my experianceits accuracy is no better than if you are a fair judge of range just by visual estimation, so I gave it up. The main problem Iworred aboutis size of the deer. A mature buck may run in my region from 200 lbs all the way up to 300 lbs, and adult does are equally different. One can imagine the problems this provides with an average chest measurement (I used19 inches). So....rather than taking a WAG I stick to what I know works, knowing the distance to every significant feature within 40 yards of the stand...