How to Field Judge Mule Deer

A mature mule deer buck is an icon of western hunting. To stalk one across endless coulees or glass one up from a distant ridgeline is what hunting this species is all about. And if you’re able to connect with a truly big buck, then good on ya’. If you have dreams of tagging a high-scoring mule deer, you need to know what to look for when scoring them in the field. We can help.

If we’re lucky, some of us will see bucks in the 140-180 range. To know if a buck will score this high, understand that its gross score is the sum total of these measurements: inside spread, length of main beams, length of points and eight mass measurements. For mule deer, there are three main components that make up a trophy-class rack: long tines, inside spread and solid mass. As a general rule, if a buck appears high, wide and heavy at first glance, then have a seat and take some time to look it over.

Keep in mind that mule deer’s body size can vary depending on the region you’re hunting. A massive-bodied Saskatchewan buck’s rack may not look big compared to his body. By contrast, the rack on mule deer in the arid Southwest might look giant on a smaller-bodied buck. Justin Spring, director of Big Game Records for the Boone and Crockett Club says mule deer antlers can vary in different regions of the same state, too. “A buck from eastern Montana might have long tines, but the frame will be spindly and thin,” he says. “In the western portion of the state, they're typically narrower but heavier.”

Beam and Tine Length

“The key with antlers is tine length because mass won’t carry you,” says Spring. But be careful, he warns. “Don’t let one really good trait fog your judgment.” The main beam on a mule deer is the bottom beam from which all other tines sprout. The length of that beam alone accounts for more than 25 percent of the overall score, according to Boone and Crockett records. How can you tell (roughly) how long that main beam is from afar? It’s all in the ears.

On most mature mule deer bucks, one ear will measure—from the white spot at the base to the tip—about eight inches (Figure A). If the deer you’re glassing has a main beam around 2 ½ - 3 ears long (Figure B), it will likely hit the 24-inch mark. That’s a good thing because it means that buck has a solid foundation on which to build more bone. Another trick is to compare the length of that beam to the length of the deer’s face, which will typically be about 10 inches long (Figure B).

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Once you’ve determined that the frame is solid, check out the depth of those forks—the deeper, the better. Good fronts are more important than the backs because more measurements come off those front tines. How do you know if the forks are deep? Use the ears as your guide again.

Don’t overlook eye guards, drop tines, stickers and kickers. All of those extra points aren’t just awesome to look at—they add to the overall score.

Spread

Super wide deer are impressive, but the only width measurement that counts for its score is the inside spread, which is the measurement from the widest points of the main beam. Just as you used ears to judge the length of the main beam, use them to judge the spread. A mule deer’s ears will typically measure 20-22-inches (Figure C) across from tip-to-tip when they’re in the “alert position”. If the ears fall inside the beams widest spread, giddy up. You’re looking at a really big deer. But again, depending on the region in which you’re hunting and the individual deer itself, ear sizes (and the distance between them) will vary.

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Mass

Mass is tough to judge in the field, but that’s okay. It only amounts to roughly 18 percent of the overall score. Just as the ears were used to judge beam length and spread, you can use the eyes to gauge mass. A mule deer’s eye will measure around four inches in circumference (Figure D). Heavy bases (six or more inches) will be bigger than its eyes. A buck that has thick beams and carries his mass out into his tines well is what you're looking for. 

Common Mistakes

Aside from the obvious pitfalls of buck fever, judging mule deer in the field has a few traps. Here’s how to avoid them. First, try to view the buck from different angles. All mule deer look big from the back because they typically have their ears pinned back if they’re walking away. While a side view will give you a great idea of fork depth and tine length, it’s tough to judge how wide the buck is. If you can stay hidden, try to get a front and side view.

Be aware of your background. Racks that have snow in the background can make them seem bigger; it’s just the nature of contrast. By comparison, a buck in the shadows or with sage as a backdrop might be harder to judge. And remember that the inside spread is the one that counts in the overall score, but that outside spread is the first thing that all hunters notice.

Practice

Now that you know the basics of field judging, it’s time for some real-world application. This is tough because the only way to know the true score of a buck is to shoot it and then measure it. There is a work around, though. The Boone and Crockett Club maintains a massive database of both trophy photos and field photos. And the best part? They’re all scored. Sifting through a few dozen of those photos while trying to guess the score is a solid way to kill a six pack with your hunting buddies and learn something.

Test

Now, it’s time for your exam. Here are three typical muley bucks from the Boone and Crockett records. How close can you get to each rack’s final score?

Photos courtesy of the Boone and Crockett Club

mule deer test

Answer key

#1 World's Record Typical
Gross score 236-0/8
Final net score 226-4/8

This is the world’s record mule deer killed by Doug Burris, Jr. in Dolores, Colorado, back in 1972. It truly has it all, except maybe eye guards, but with an inside spread of more than 20 inches and main beams that measure 30 and 28 inches, weak eye guards are okay. What it might lack in mass, it more than makes up for in tine length. Look at the depth of those forks—all four are nearly identical! Can you guess the inside spread of those main beams? It’s nearly 31 inches.>

#2 180-inch Oregon typical
Gross: 183 1/8
Final: 181 5/8

Back in 2009, Charlene Winkler killed this Oregon buck in Malheur county. If you were field scoring this, it’s likely that you’d first notice the frame, which is solid. But those shallow back forks are hard to miss. Don’t get me wrong, this is a great deer, and each main beam measures more than two feet. Plus, this deer is incredibly symmetrical with less than two inches difference. While it’s tough to see with one ear pinned back, the inside spread is an eighth shy of two feet itself.

#3 200-inch Idaho typical
Gross: 216-5/8
Final: 200-1/8

Scott B. Weeks shot this toad in southeastern Idaho a decade ago. It’s got a little junk that comes off the back forks, but don’t let that stop you because those eye guards make up for it. Be sure to compare the ears to the inside spread of the main beams. A mule deer’s ears will typically measure 20-22-inches across from tip-to-tip when flat like that. When they’re alive, that’s the “alert position” as they listen to you trying to take off your pack. The inside spread on this buck, the measurement from the widest points of the main beam, measures a tad over 24 inches. Line those up and tell me those ears aren’t a good measuring tool.