Rule of average. If its the first deer in the field and its alone. Then 90 percent of the time it's a little buck . Just my thoughts. If three or more deer are in the field it gives a better reference to compare to. Ex long nose nanny . Most of the time a little young antler less buck will be kinda arch backed as best as I know how to discribe. Kind of oval backed . Any way to avoid shooting a nub buck just wait until there's more out there to compare to . Thanks