My friend invited me to go along with him to hunt in Montana on his Uncle's land. All I got right now is my .308, I got some 150 grain Winchester XP3 Premium loads for the hunt. I was wondering if this would be enough, could it also take a Brown Bear if needed ? The reason I ask this is, his uncle swears there is a big trophy Brown Bear in the Woods, but he is extreamly aggresive and territorial. Also, if the XP3s arn't a good choice in .308, what is ?