I agree with most of the previous comments
a, A 30-06 is a great round and loaded with the proper bullet it will kill what ever walks the earth.
b, You need to ask your guide what he will let you carry.
c, Some guides are happier if the customer shows up with a 30-06 that has been shot and carried rather than a 416 that has been shot twice,
d, bears are damn tough, bigger is better, but only if you can hit with it.
e, penetration is the key, not expansion, so choose bullet leaning that way.
f, I would be more comfortable with my 338 -06 or my 375 H H but i would not be afearing to hold a 30-06 with good bullets if i got a chance to take my time and shot the bear from a good hold.