I have used the Sierra #7150 80 gr Single Shot pistol bullet in my 6mm-225 Win 14" Contender at 2700 fps to kill deer with. It killed every deer but all my shots have been inside 100 yards and the bullets really came apart on bone. If you are going to be shooting longer ranges then this bullet may work better. That is if you can find any of them, I can't find any reference to them for sale anywhere. Sierra may have stopped making them. I really believe that the Sierra 85 gr Gameking HPBT would make a good deer killer, it does in rifles. You should be able to get 2900 fps or so in your 243 Win. The 85 gr Nosler partition would be a good one also as well as the 90 ballistic tip.