Len, most of the time, I am not able to get into a prone position for taking a shot at a speed goat. I prefer the sitting position when having to take a long shot but that is when there is no wind to blow against your body and in Wyoming that blessed wind does blow often as not.
I have also run into times, when there was no larger rocks to lay up against or put your pack on etc. This can make it hard for those long range shots on the ghost of the plains. Hey, I have seen several hunting shows, using those cardboard painted antelope one simply holds in your hand and hide down behind it......They seem to work on camera, just don't know. I would rather reach out and touch them with my 1/4 bore 25-06 and a good 100 grain bullet sailing at 3300 fps.