Thanks for scouting for me!!
I think either the prongs are really low or he is a really tall buck.
Looking around for an idea of how wide a pronghorns head is I found this picture.
If you measure the same perspective on both of the pictures, in the one in the first post, the head is actually wider than the height where the prong comes out from the horn. In the one from the field judging pictures, the head is not near as wide as where the prong comes out from the horn.
So I think it is a good buck in the first picture, but I also think that the prong is pretty low on that buck.
With that said, the picture I linked to above is an 80" buck and if you use the same perspective measurement of the width of the head, the overall length of the horn on both goats is about the same. The 2nd mass measurement is going to still be below the prong so it shouldn't affect the score a whole lot, but I guess it could make a couple inches difference. Sometimes to me the score on a pronghorn doesn't exactly match up with the way it looks though and a 16" tall 78" goat with a low slung prong often looks more impressive to me than a 15" tall 80" goat with a high prong and big upper mass.
From behind, mass looks good, but that could also be the way the horns are angled. Pretty much impossible to tell on the prongs from that angle.
I'll be driving over 3,000 miles round trip so I don't think I will be shooting the first buck I see, but that one would be hard to pass up if he looks as good from the side as he does from the back.
Thanks again for the help and information Jeb!