A friend told me of this method to quickly score a buck. I looked on-line and found this set of instructions for doing it. I've tried it on several mounts and find that it works very well.
Getting a fairly accurate score, quickly, is not that hard really, but it does take some practice before you'll be really good at it. What I like to do is to quickly judge mounted trophies and then actually put a tape on it to see how far off I am. After a hundred or more of these, you will find that getting within 5 score points (inches) is pretty easy. Almost anyone can be within 10 inches after just a few dozen test runs. But what do you do if you can't access several dozen mounts? Well, here is a fast, very general way to get an approximate score.
First, look at the smaller half of the rack. Almost all deer antler sets will have some asymmetry. In other words, one side does not look exactly like the other. Try to use the smaller side if possible. Why the smaller side? BEWARE OF GROUND SHRINKAGE! Antlers almost always tend to look bigger when in the air above a live deer's head than they do on the ground by a dead one. By using the smaller side to start this process, you build a bit of ground shrinkage into the system. Now, add up the total tine length on that one side. You can use the ear of the deer as a reference. They are generally 7 to 8 inches in total length from where they join the head to the very tip. Now double that score and add either 80, 90 or 100 for the rest of the rack. A decent buck, with normal looking antlers, will generally score about 80-85 inches of base score (main beam, spread and mass combined). If the rack looks pretty heavy, the beams reach his nose in a side view, and are as wide or a bit outside the ears, but doesn't look HUGE, he will generally get a score of about 90-95 for the base score. A deer that has it all; width, long main beams and real good mass, will score 100-105 base score. Mass is very important in this computation because it is measured 8 times total, so just one inch in circumference at each measurement can add 8 inches of score. Normal mass is about 4 and 1/4 to 4 and 1/2 inches at the C-1 (first mass measurement made at the smallest point between the base and first typical point). As reference, the eye of a deer is roughly this same circumference. Spread will fool ya if you're not careful. Add just 3 or 4 inches of spread and most people will guess an added 10 inches or more in score. Usually, if they get spread, they give up mass or beam. If they get mass, they give up spread or beam, and so it goes, but it all averages out real close to the totals given. ONLY the deer that has it ALL will get that 100-105 base score. Don't get fooled!