I cant say how well they are in the 338 but in 35 they are my main choice of hunting round. I have used them on black bear, moose(both cows and bulls) and this last fall on a whitetail doe. Anything I have ever shot with them never did go very far. I did find that they do seem to perform best right around the 2850 range, any faster and penetration suffered as the bullit came apart too quickly, now having said that the annimal did still die. Huge trauma to all the organs in the chest cavity and massive internal bleeding. The only one I have had complete pass through is with the doe though so if your looking for a round that makes large exit wounds on heavier game this isn't it.
I also should addthat I am using the 225 grn, I just read the WHOLE title of your post so I'm not too sure if anything I put in there is relavent to you. Apologies if it's not