I agree with Elkkamp on this. If I was in your situation I would opt for at least a 165 grain, but my first choice would be a 180 grain bullet. Bullets are cheap on a hunt of a lifetime such as this. I would use the 180 grain nosler partition, trophy bonded bearclaw, winchester failsafe or other premium bullet. I have used the nosler partition with great results, but have heard the others do well too. Not only is the 150 a little light in my opinion, but the regular core lokts are not heavy duty enough if you need to penetrate some big bones, which can always happen. I think the new Remington ULTRA core lokts might be ok, but the regular core lokts I only feel comfortable using on deer sized game.