The 44 Mag in a rifle at 1500 fps with a hard cast 320 gr. bullet will work just fine, hell it will work in a handgun as well. I would be more concerned with the iron sights, than the caliber you selected. A lot of guides are not to sure of us handgun hunters, it is like they do not see a lot of us.

Shot placement is key in what ever you use. As far a sights go, I used my 510 GNR with ion sights, and got my bear at 6:00 PM, with low light, and a light rain coming down. I did how ever bring my 6 inch BFR 500 Mag with a red-dot on it, if it got to dark for me to not see my iron sights. A red-dot will extend your ability to put the dot on the bear in low light.
As long as you can see your sight well, you will not have a problem. When it gets low light and a black bear comes in, they can be hard to see and see your sights, even with bright sights. Have you considered a red-dot or low power scope on your rifle?
But if you are ok with the possability of not getting a shot in low light, then just use your iron sights. Maybe bring a back up handgun with a red-dot on it to extend your time on stand. Nothing like having 30 min of shooting time left, and not being able to see your sights.
My bear hunt this year will be with my new 475 Linebaugh and a red-dot installed. My back up gun will be my 4 inch 500 Mag.