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.
January: Last years Season has ended.Time to start focusing on next year's season. You will need to find out what bucks might still be alive that made it through the last years hunting season. After the hunting season sometimes bucks and does might leave your area and go to another traditional winter yarding area. But they will return to the area around late February early march to spend the rest of their summer there. At this time of year, the use of scouting cameras will be the tool in...