150gr for elk with a 300 mag of any kind is a recipe for problems. Too light a bullet for the cartridge and the animal IMO. Poor shot placement only makes a bad situation worse. 270 has the power to kill elk with the right bullets, but it's not my favorite caliber though. I just happen to be able to shoot larger calibers accurately, so that's where I tend to migrate to. If I want a high velocity, meat damaging load like what the 270 fits into, I'll use a 7mm mag or a 300 mag in a heavy bullet. If I want to do less meat damage and still insure a kill, 375H&H all the way. Remember, velocity is what destroys the meat, its not always bullet diameter. Either way, shot placement is king and trumps all else. If you can't shoot it accurately, improve your shooting, or figure out what is wrong with the tasco scope that sits on your rifle =D