HHI 812,
I do not have any experience w/ the performance that you seek. However, I am also considering a 338 cal single shot pistol for deer and bear. I am thinking the Nosler BT in 200 or 180 would do well. I also discussed some things with the folks at Hawk Custom Bullets, Salem, NJ. 856-299-2800. They have good information on their web sight @ hawkbullets.com. and were very helpful when I called. If they do not have the bullet you need in their standard line up, they will make a run of a few boxes for you. They can adjust the performance of their pure lead w/ pure copper jacket by using different jacket thicknesses.
So, if you don't get any 'hard evidence' feedback here, perhaps the folks at Hawk can help you get what you need.
Good luck, and good hunting,
Tapper