If you’re expecting to encounter a bear (coming into your home or you going into their area) you should probably consult the prior thread:
And honestly, any practical handgun is a very poor choice against a bear. A shotgun, or as I opined in that thread, a higher caliber short carbine (45-70) would be the far better choice. Again, a handgun sacrifices most of the advantages of a firearm for a huge advantage in weight/size/concealability.
Of the common calibers that are available, vaguely shootable, and so forth, than yeah, if I had only that choice I’d go with a heavy loaded S&W Revolver in .44 Mag. But it’s still a poor overall choice.
That’s because a .44 magnum revolver carries 6 rounds and a Glock 17 carries 17 rounds, and police generally prefer more bullets over more powerful ones.
It’s still a poor choice if you’re looking at your safe and wondering, hmm, that bear over there is charging me, so which of these guns will I pull out and use? As you intimated, the advantage of a handgun is that you’re more likely to have it with you. I have a chest rig for my lite .44 magnum and it’s comfortable (enough) to sleep with and have on me all the time.
It can be shot 6x in decently rapid succession in, say, 2-3 seconds. Faster, with training. But you’d better be ready and have a good grip on it.
But this is a thread about kinetic energy and not about choice of firearms. .44mag has decent KE, especially from a longer barrel.
The key thing about KE against a charging bear, or really against any target, is can you reliably place rounds on your target? A 9mm NATO is a lighter round and generally has less KE, but if a charging bear gets shot 10x with 9mm NATO, I’m willing to bet that he’ll be stopped (theoretically speaking; I’d rather not test this). And with training a shooter can swap magazines quickly and place another 10 rounds into that bear.
So if we’re asking about the KE of any single round, that’s different from the KE of 20 rounds of 9mm NATO placed rapidly on the target. I’ll take 20 rounds of 9 over a single round of, say, .50 BMG.
It’s all about control and shot placement. Especially when one is crapping their pants with a charging bear only seconds away, but it’s always about control and shot placement.
As a general rule my advice is to get the largest caliber (or similarly, the highest KE) that an individual can effectively control. The answer will be different for different people.
I don’t see any disagreement. My CCW weapon (not that I carry anymore) is a S&W M&P9c with a mix of normal and +P JHP. But I wouldn’t use it as anything other than a noisemaker (or last ditch option) against a bear.
Really, as I said earlier, there are just so many damn factors in deciding arbitrarily what is a handgun or even handgun ammunition, as well as barrel length, the action, and so forth that the question would have to be reframed and substantially narrowed to answer the question. And of course, we’re leaving out KE at what range as different types drop off more quickly than others.
I invite our OP @Wesley_Clark again to talk about how they want to go at it. And will make the observation that comes up with most firearms when it comes to KE - how much of it is wasted? Because, one of the reasons there are so damn many magic bullets and calibers out there is the competing desires for penetration and energy transfer.
Because a very high KE round (normally from the V^2 part of the equation) tends to penetrate, especially with FMJ ammunition. That means comparatively little of the KE is transferred into the target. Now against a bear, a bit of penetration to reach the vitals is for the best because, well, they’re bigger than humans. But there’s a good argument to be made that something that penetrates just enough to be deadly and therefore transfers as much energy to the target it a better measure of effective KE.
Very true if a big animal is charging you. Because you want to shoot it in the brain, ideally.
A bit OT, but when it comes to big animals, a bullet in the center-of-mass won’t immediately stop them. It might eventually succumb to its injury, but in the meantime it will have amply opportunity to kill you. If you want to immediately stop it with a gun, you need to shoot it in its brain. The caliber is not all that important, but it takes a lot of skill to pull it off, especially when you’re under extreme stress.
One person who perfected this was W. D. M. Bell. He was a big-game hunter in Africa. His contemporaries were using big, heavy, big-bore rifles to take down elephants, and with only limited success. Bell took a different approach: he became an expert on the anatomy of the elephant, especially the brain and surrounding bones & muscle. He would carefully place each shot to hit the brain, and he did it with a small-bore rifle. He was extremely successful at it.
So unless you know you can reliably shoot a bear in the brain, bear spray is probably a better solution.
A short barreled AK (“Draco”) or AR-15 pistol is legally defined as a pistol by BATFE, so yes it counts legally, but you may or may not consider it as it’s a traditional rifle caliber.
Note that the aforementioned .460 S&W can be rather practical, because as a revolver cartridge it’s basically an elongated version of previous cartridges, and can safely shoot the shorter ones, whether you want something with less recoil or just cheaper to shoot at a range. For the .460 you can shoot: 1) .454 Casull, .45 Colt, and (if you wish, but it has more collector value) .45 Schofield.
This can be factually answered by muzzle energy measurements, but at some point the “most powerful” becomes a measure of oneupmanship, as at some point it becomes not pleasant or practical to use. However: it sounds like you have a less academic and more practical question. Most Alaska bear guides use something along the lines of: 1) whatever rifle they plan on using for hunting, 2) 12 gauge, 3) .44 Magnum, 4) 10mm. The last is generally a choice of additional capacity while being manageable. All of these should be paired with bear spray, you can find discussions about whether one is better than the other, but really, why not both?