I think muzzle energy is a poor indicator of terminal performance. I believe using power factor (momentum) is better. Here's my example:

Which is more effective? A baseball thrown at 75 mph or chest passing a bowling ball at 10 mph?

Baseball: 5 oz (2187.5 gr), 75 mph (110 fps), 59 ft-lb, 241 PF
Bowling ball: 10 lb (70000 gr), 10 mph (14.667 fps), 33 ft-lb, 1027 PF

Bottom line- the baseball may sting, but the bowling ball will knock you down, even though the baseball carries more energy.

Now, let's compare 2 "standard" loads; 124 gr 9mm+P at 1150 fps and a 230 gr .45 at 850 fps.

9mm: 364 ft-lbs, 143 PF
.45 ACP: 369 ft-lbs, 196 PF

Both have essentially the same ME, but the .45 dominates in power factor. Is the .45 better in terms of stopping power? Probably.

The .45 also has the advantage of a larger hole. Unlike the FBI, civilians don't need to worry about penetrating body armor. That's what rifles are for. Asking a handgun to do that and choosing a load because of it is asinine.

FWIW, I carry 9mm, .38 and 10mm based on personal preference. I'm not trying to push one caliber over another, just looking at it from a different angle.

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an actual conservative