Ok, let's go beyond theory, and use Scientific Theory. Here's a website that will put us in the right state of mind:
http://www.deerstalker.com/kov.htmFor those who don't want to spend a lot of time there, it breaks down to this: Taylor used the formula "
Momentum X Calibre" to arrive at levels of killing power, with a few anomolies. Bekker modified the formula to "
Momentum x Sectional Density", which eliminated and explained Taylor's anomolies, while giveing a much more accurate picture of killing power.
Here's the equation: (weight x velocity / 7000) x (weight / (7000 x diameter x diameter)) = Bekker improved Taylor Knock Out Value.
So let's put this Theory to work for us.
First I'll use similar bullet weights and velocities.
Second I'll compare (relatively) optimum loads for each calibre.
Let's begin.
1) .480 calibre, 400 grain bullet, .476 diameter, 1400 fps.
(400 x 1400 / 7000) = 80 Momentum
(400 / (7000 x .476 x .476)) = .252..... Sectional Density
Answer x 80 = KOV of 20.1761) .454 calibre, 395 grain bullet, .452 diameter, 1400 fps (I couldn't find 400 grain bullets anywhere).
(395 x 1400 / 7000) = 79 Momentum
(395 / (7000 x .452 x .452)) = .276.... Sectional Density
Answer x 79 = KOV of 21.82(Bekker improved Taylor Knock Out Values of 20-22 are in the 180gr. 300 WinMag range, just for reference)
Here we saw that the superior sectional density of the slightly lighter .454 round has a more deadly effect than the slightly superior momentum of the .480 round.
2) .480 calibre, 425 grains, .476 diameter, 1250 FPS.
(425 x 1250 / 7000) = 75.89 Momentum
(425 x (7000 x .476 x .476)) = .268 Sectional Density
Answer x 75.89 = KOV of 20.332) .454 calibre, 395 grains, .452 diameter, 1350 FPS.
(395 x 1350 / 7000) = 76.18 Momentum
(395 / (7000 x .452 x .452)) = .276 Sectional Density
Answer x 76.18 = KOV of 21.042) And another "optimum" .454 load
.454 cal., 335 grain, .452 dia., 1625 fps.
(335 x 1625 / 7000) = 77.77 Momentum
(335 / (7000 x .452 x .452)) = .234 Sectional Density
Answer x 77.77 = KOV of 18.22These calculations illustrate the ability to handload your argument in either gun's favor. But either way, if you're quartering an elk in bear country you'll be most confidant with the round in your calibre that optimises both SD and Momentum, which is why I put up both perceptions of "optimum" for the .454 in the last comparison. But getting the .480 into better SD ranges might mean pushing bullet grain weights into .475 Linebaugh territory.
Bottom line: It's not all about muzzle energy, or even energy at distance. If two bullets (of the same design of course) weigh the exact same, and leave the muzzle at the exact velocity, the lower caliber (narrower) bullet will retain more velocity and KOV at any given distance, and will have less of a propensity to be slowed down in any medium (air or bear), and will therefore penetrate deeper while imparting more energy. Unless maybe if it pops out the back side and puts that additional energy into a tree... Let's put it another way: If two rounds reach the target with the exact same level of energy/momentum, the one with the better sectional density (again, the lower caliber/thinner one) will have less of a propensity to be stopped, and will penetrate further than the larger caliber bullet, even though they both deliver exactly the same level of energy.
Woah, that might take us below the bottom line. If one imparts it's energy faster, in that it penetrates less deeply while imparting the same level of energy, it stands to reason that as long as it penetrates deep enough, it will impart a greater shock to the subject. This goes into scientific theory that I'm not prepared to argue.