Back in the 60s and 70s, I spent the early winter months with my left eye plugged into a spotting scope watching mule deer bucks. It was in those years that I came up with a system to judge the rack size of a buck in the field. It came about after many hours of judging them on the hoof, and then in the spring picking up their drops and gross measuring them. While guiding during the same time period, I measured many harvested bucks. These two practices gave me the opportunity to develop a rack bracketing scoring system. The motivation came while I was guiding clients who required me to know the B&C gross class of the buck before they squeezed the hammer.
Let me go through my system for field judging a buck. You can start by using the ears and a few other simple rules to help determine if the buck is a 160, 170 or 180-class gross buck. This is my “Rack Bracketing System” for field judging a gross rack score. The system isn’t designed to give a net score, but with some practice you will be able to narrow the gross score down to high, mid, or low 170, 180, or a super 190- buck.
First determine the distance between a buck’s ears, ear-tip to ear-tip across the forehead. This measurement will be used to evaluate inside spread width. Unfortunately mule deer ears will vary in length from 9 to 10 inches depending on the unit or state. In addition some bucks in certain units will have bigger heads adding to the ear tip to ear tip length. In my experience Wyoming and Idaho mule deer, tip to tip, will vary from 21 to 23 inches. However in Colorado and Utah ear widths will be 24 to 25 inches. I guarantee that there will be exemptions to the rule in all western states, but this is a beginning benchmark. Saying that, you need to gather your own ground knowledge for the units you personally hunt.
My first rule for judging is what I call “good fronts will make up for bad backs.” The “fronts” include the three measurements: