Well, I am a scientist -- or so my Bachelor's degree says (never mind that it's a BS! <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />) and know a little about theory. I also know a little about reality and a bit about how theory and reality get along together.
Sound, proven theory (theory that's also reality) says that the Law of the Inverse Square favors shorter, fatter cases with the same capacity, because they put all the powder closer to the primer for more-uniform ignition.
But the magnitude of the advantage is probably too slight to worry about. Once again, I have to quote the late Homer Powley's very pertinent parallel. I'd just said something about how often we know that a certain factor is involved in ballistics but it doesn't have enough influence or effect to deserve practical consideration. Homer immediately said "That's right. The moon affects the trajectory but not enough to worry about."
I suspect -- not having messed with any of the new short-fats -- that their interior-ballistics superiority is about as great as the moon's gravitational tug on the bullet. The moon affects the oceans (tides) visibly and measurably, of course -- but then there's a heck of a lot more mass in the oceans than there is in any bullet, and gravitational attraction is proportional to the masses of the moon and the oceans -- or the moon and the bullet in flight.
The big real attraction of the short-fats is that the day the first one appeared, the multitude of buyers who HAD had the latest and greatest suddenly became -- overnight -- a step behind the market. No one can make any of the new short-fats out of a .30-06 case.
At the writers' seminar where Remington introduced their 8mm magnum, the Remington people (as they usually do at those affairs) proudly told the group how great the new cartridge would be for Remington's sales, their market research that led to it, etc. When they finished and asked for questions, Elmer asked "What's it good for?" The other writers got a kick out of his question but totally missed his meaning. He wasn't questioning its usefulness (IMO), just pointing-out the crucial
practical point that shooters want to know but the proud presenters had not addressed at all.
Their usefulness to shooters and their ballistic superiority aren't the main reasons for any of these new announcements, IMO. "It's the sales, Stupid!" Cash flow, not interior or exterior ballistics, is the primary advantage offered by the short-fats. It may be their only claim to fame for all I know. I'm not sure that there's any real, practical ballistic advantage -- or that it's significant if there is one.
(But what do I know? My dad, stumped by a question on a test, poked a hole in his paper with his pencil, drew a circle around it, and wrote "All I ever knew about ____ just went through this hole." When he got his paper back, the professor had circled the hole on the other side of the paper, with the note "It hasn't come out this side." <img src="/ubbthreads/images/graemlins/grin.gif" alt="" /> )
