About 11 years ago I took my only hunt in Alaska I took my 45/70 for Kodiak. The guide stated he would rather see me shoot some thing better at a long range but he said if I felt confident with the 45/70 that it would work. I shot my bear at about 45 yards and it took 1 step and dropped dead.
I think the most important part of hunting any dangerous game is a good back up with you. The guide that took me had a 458 winmag (I think) and my father (who was not hunting but came to support me) had a 44 mag on his hip.
Shot placement is everything! I would rather take a round of 50BMG to the foot than a 22short to the base of the skull.
all 26 of my guns are 45/70 govt, 357 mag, 22 or 12 ga... I believe in keeping it simple. Wish my wife did as well...