I'm not sure which side of that line the .45 ACP lies, but I wonder if many animals would be encouraged toward a person repeatedly firing 10mm 200gr HC FN bullets @ 1,300 fps at it.
That's not a charge situation, but should
get you charged.
...............................................
Look, bears have been DRT with a rifle shot and bears have charged after being hit with rifle shots.
Lives have been saved by handguns in DLP situations and sometimes they have been made worse.
Pick the proper search terms and have a go at Google and Youtube. You'll find examples of both.
Carry what you want and good luck with it.
That said, I prefer a handgun to pepper spray.
I'd rather have a 12 ga. over a handgun and a rifle (of almost any cartridge) trumps all.
I too would rather have a 12ga or rifle if actually being charged. But I carried a handgun (in my case, a FA .454 with 360gr HC FN bullets chronoed at an avg of 1,503 fps) while fishing the rivers, and was glad because carrying around a rifle while fishing and screwing around for hours at a time nine straight days after I got my brown bear with my rifle would have been, to me personally, somewhat annoying.
And I brought an anti-tank version of a handgun, but I would not have felt completely undergunned by a 200gr .40 caliber HC bullet moving at 1,300 fps. I know you can find some things to support both sides of almost any opposing arguments, as you say, but I haven't seen the number of specific incidents supporting the "better file off the front sight" argument as I have seen supporting the opposite. And I'm talking actual specific reports, such as:
"'The man, who was in the lead, drew a .45 [ACP] caliber semi-automatic pistol when they heard a noise coming from the brush. When the bear emerged from the thicket and ran toward the other hiker, he fired approximately nine rounds in its general direction. The bear stopped, turned, and walked back into the brush, where it quickly disappeared from view,' said the [park's] release. ... The bear was found dead in a willow thicket approximately 100 feet from the pistol casings ..."
LINK. I freely admit that I could be wrong, but people, like me or anyone else, must make judgments based on what we have observed and been able to learn and the logic that seems most appropriate. There is disagreement on this issue, so people can't simply "rely on the experts" to decide because they don't agree. I have seen countless animals from squirrels to humans to deer to brown bear being shot with some kind of firearm. There may be countless examples that I just haven't seen, but in every instance where the animal could, he/she went the other direction if at all possible and as quickly as possible. The 10mm load described above is essentially a standard .41 Mag load from the past. I know that talking about rapid-fire shots at a bear sounds intuitively silly to many, but I can empty my G20's 15+1 capacity pretty quickly, and am probably better at shootinig it, especially with folow-up shots than with my .454 Casull. And I just haven't seen any really compelling collection of data or even annectdotal specific reports that show me that, even a big bear would simply laugh off being pelted with a lot of .41 Mag bullets in a short period of time and just march toward the source of the pain and shockingly-loud noise. It's possible that I'm overlooking something (and I'm not saying it has never happened), but if I had to bet, one way or the other, I would think many many more than 50 percent of brown bears would flee when being pelted with such projectiles, just like every other animal I've ever observed, and just like in the reports I've read, like the one quoted above.
It appears that there is an average of something like one or two fatal bear attacks per year in
North America (of course more are injured too). If someone is hiking in bear country and can't shoot a .500 JRH well and doesn't want to lug along a 12-ga or .375 H&H every time they go out into the wild, I just see nothing wrong with relying on the equivalent of a fast-shooting .41 Mag that's easy to carry, draw, and shoot quickly. Of course, he might be attacked by a rare angry bear that charges into .41 Mag explosions and bullets, but it might work like the incident above, or more likely, he won't get attacked at all, but will have a decent survival tool (for emergency meat hunting, signaling, and inti-personnel protection as well). And of course, I'm not questioning anyone who prefers something else. I'm just defending the judgment of those who do choose to rely ono something like a 10mm with hot and heavy hard cast loads.