Below is a pretty good buck my brother took over the weekend in my native CO. This buck was taken in an area known as South Park which is basically a high mountain meadow. It sits at about 8000 ft, runs for nearly 70 miles and is surrounded by snow capped mountains.
To my knowledge he hasn't put a tape to it but he says it will be between 15 1/2 inches and 16 inches. For CO, this is about as good as you can reasonably expect a pronghorn buck to be. I especially like the way the horns hook way back. Only the oldest bucks do this.