I have killed 9 moose with my 7mm mag, none run off; go down easy and the boy always finds that nosler on the back inside of hide when we take hide off. I would never use anything lighter than a 375 mag, for bear, sometimes carry the 45-70 when hiking up high, short & light. My friends all had 300's and 338's.
I sneak in on blk bear in devils club berries all the time in moose season, get within 10 yards of them then sneak back off, so satisfying too. I would never attempt that with grizz, around where I live they only get up 600-800 lbs, small interior bear; but they all still look quite big to me just they same. Don't piss with them and wish there were fewer of them around. They really hammer the moose calves.