All the anecdotal evidence makes my head hurt, especially from people who've never actually seen a moose outside of a zoo much less a Brown/Grizzly bear. So here’s mine: I used to fly seasonally for a little air taxi who specialized in hunter drop-off/pick ups, little bush airplanes with big tires off hacked out strips in bush AK. Company policy was; an average sized bull moose weighed 750 lbs, bone-in quarters with sawed off the skull rack. No hide, no gut bag, etc… I weighed several rear quarters in the 200 lb range. Moose also aren't hard to kill, poke a hole or 2 in the lungs and they go down, just like any other ungulate.
Bears. Basically, don't worry about it, any rifle you have in your hands will work. Just shoot them in the head and get out of there. Hunting them is one thing, defending from them is something else. You don't have to kill a charging 1000 lb killing machine in one shot, just stop the charge. Hurt bears bad enough and suddenly they don't want anything to do with you.
We hunt with 6.5’s, 270’s, 7’s up here in AK, have been for decades. The old trappers only had 30-30’s for over 50 years. When the ‘06 came around it was revolutionary, and people couldn’t get over how much power that round had, and the state didn't see widespread use of it till the 40’s when WW2 kicked off up here. Don't over think it.