As Ajo said shot placement will make any bullet work.. Is the reason you want to use a 150gr bullet because your gun shoots the best groups with it or because you like that weight the best? I would step up to the 180gr. Not sure if you have tried a heavier grain bullet in your gun or not.
I'm sure a well placed bullet will do fine, but like others have said here, I go with a 180gr in .30 caliber for Elk as well, leaving the lighter bullets for deer. I happen to use the Nosler Partitions, but get a good penetrating bullet like mentioned above as well.
If you pick up a reloading manual that has a balistic table in it you will find that the magnum calibers were designed to shoot the heaver bullets for better performance of game. The light bullets will work but then why did you buy a magnum rifle speed isn't everything.
When hunting whitetails there are many different languages being spoken afield that I key on when outdoors. All these little creatures living around whitetails have something to tell us if we are willing to listen.
My favorite tattletales of the outdoors are a handful of little birds that live in my state of Ohio. Maybe yours too. A tip for the upcoming season.
There are Blue Jays, Cardinals, Chickadees, Killdeer, and Sparrows that all have language...