Really not that much difference. 130's would start out a little faster, but slow down faster too. Both weights work just as well for hunting. More important is the type of bullet than the weight. I would say the Sierra's are probably not the best bullet for elk, regardless of the weight. And other than that I'd say the only small difference you'll see between a 130 and a 150 grain is the heavier bullet will have a little more recoil.