LAST EDITED ON May-28-06 AT 04:16PM (MST)[p]Elkaddiction hit the nail on the head! Everything he said is right on the money! Mass is definitely very important if you want a high scoring horned animal (sheep, goat, antelope, etc). Mass isn't nearly as important in antlered animals (deer, elk, etc as it is for horned game because mass doesn't take up as large of a proportion of the overall score with those species). Horn length isn't nearly as important on horned species but it takes just about everything to make B&C. If you think about it 1" in length on either horn equates to 2 pts in the overall score. There are 8 total mass measurements and a fraction of an inch x 8 really adds or detracts considerably from a score.
Each general area in the Western US (and even within a state) generally produces different confirmation in horn measurements (that goes for sheep, goat, antelope, etc). For example, it is fairly common to find 16" antelope in NMex while there are very few 16" antelope in most areas in Wyo. Most of the reknown B&C units in Wyo produce super massive bucks and if you see one over 16" in length he is likely a B&C contender....if he has decent prongs.
I would visit a taxidermist in the area you will be hunting and get a close look at representatives from the particular area you will be hunting. You may even want to put a tape on them to get a better idea. If you don't have time to scout out your area or go to a taxidermist another option is to look at the B&C books. They often list base, length, and prong measurements for each county in a particular state.
I have never liked using ear and eye or any other body part to size up horn length or mass. A buck may have a stubby, short nose, dinky eyes, short ears, etc that will totally screw up your estimates. I have been fooled countless times by trying to judge from ear length, etc. Just because a buck has prongs high on the horn doesn't mean squat and more times than not a buck with that confirmation is fairly thin horned. A super massive buck may seem short and stubby in appearance in comparison. I've been fooled more times by looking at horn length in relation to height of prong or ears more times than I care to admit.
Another thing to consider is to get as many angled looks at the buck as you can. If you just have one view you may be sorry you shot a buck. Both side and front views of a buck is critical. If you are uphill or downhill this can also make it tricky field judging.
One of the best methods I've found for judging any animal is to compare measurements to the length of a dollar bill. $1 is exactly 6" long. Where I hunt the minimum buck to make B&C generally has to have 6" prongs, excellent mass, and 15 1/2" horn length. Average bucks where I hunt in Wyo generally have a little over 6" mass at the base and 2nds. If you can wrap a dollar bill around the base and have another 1" to go you are looking at a super buck! I love those dark, massive horns!
As mentioned above a B&C buck usually takes about everything. Where I hunt in Wyo I look for the following to make mimimum B&C: 6 1/2" base and 2nds, 4"+ 3rd mass, 2 3/4" 4ths qtrs, 6" prongs, 15" length. If you add all of those up you come up with just over a 80" buck.
I have to agree that pronghorn and mtn goat are about the toughest game in NA to judge!