Well, we may debate about whether .44 Mag is more than a marginal bear-defense round, and whether you can land better hits with a revolver or a shotgun, and whether you will have the more powerful shotgun with you when you really need it -- BUT, I'm pretty certain I've never heard anyone put forth the idea that a .45 ACP would be much more effective than a fly-swatter against a grizzly bear.
Sure, sure, shot placement is KEY ... I think in that case, your best bet will be to hold your fire until you're really in position to make the kill. A .45 ACP shot from inside the bear's stomach should be able to penetrate to the heart.
You, Sir, are my new hero ;-)
I haven't spent a lot of time on this site, but after reading your posts in this thread I am reassessing my firearm forum time management
The .44 Mag is near and dear to me. I grew up using long guns in the backwoods of Oklahoma; was a proud owner of the Expert Marksman badge in the U.S. Army; and always considered handguns to be mere curiosities & playthings.
It was only a year and a half ago that my new wife expressed interest in acquiring a handgun to replace the .45 "Magnum" she had as her car gun in Alaska. This being my second marriage, I was able to restrain myself from scoffing, "There isn't a .45 Magnum!" :-| I never did figure out what exactly she was describing - my best guess is a +P .45 ACP. I asked her why she needed such a powerful handgun, and she proceeded to enlighten me to an apparent commonplace in Alaskan culture wherein everyone (at least those that are not Darwin Award candidates) carries a BIG Magnum everywhere in order to defend themselves against BIG Bears - esp. the Ursus arctos horribilis - and other HUGE animals (moose roadkill?).
I thanked her for the lesson and suggested that we start her off with a 9 mm as there are no Ursus arctos horribilis here on the California Central Coast nor other massive animal threats. And her small frame and light body weight coupled with her aging joints (we are no longer spring chickens) are not exactly amenable to Big Recoil firearms. She has been quite comfortable with that and absolutely refuses to shoot the .44 Mag Desert Eagle, S&W Model 29 Classic, or even the Glock 27 that I bought for us to try out.
I, however, LOVE my Desert Eagle. It was my first .44 Mag. I did not plan it that way. A shooting buddy decided to sell his & a mutual buddy whispered that in my ear at the range one day. I immediately bought it. Then I learned how to reload ;-) Which is an absolute must in order to have any pleasure with the ammo finicky/picky DE :-| I quickly found my perfect load. One hot enough so that DE cycles perfectly 100% of the time and have subsequently run over 3K rounds through it in the sixteen months I've owned it ;-)
Six months later I was buying ammo at one of those tricky gun stores - you guys know the ones; where they place delectable treats in glass counters right at the register? And there, under the glass, was the most beautiful S&W 29 Classic ;-) I bought it.
I have since won our local Bowling Pin match revolver competition with the Smith and the semi-auto competition with the DE
I apologize for the overly wordy, long post. For those who persevered through it - thank you. And thanks to those who gave excellent advice to the OP ;-)