lol, an air horn? oooook.
I've spent a good amount of time hiking/camping in griz country, and generally zimkok is right. I love my guns and all, and I carry a .45 mag (anything smaller won't do shit anyhow) when I'm out, but I bring spray too. First, if a bear were to attack, the odds of you shooting a large bear in a place that will take it down, even with a decent caliber and you are a good shot, isn't great. A second or 3rd? Unlikely.
Bear spray is effective at a good distance, and isn't a one shot and it's done deal. In the event of an attack, even though I'm pretty good with the revolver, I'd still reach for the spray first.
Are you saying a 357 mag isnt good enough, that it has to be a 45 mag?