Here is my .02 on the matter.
The 338-06 is a great round but I would rather have a 30-06 loaded with 200 gr + bullets, I just am not sure it is much more gun than a 30-06. If I wanted to 338 I would look at the 338 Win Mag and use something like RL 15, Varget or H 4895 for performance a bit better than the 338-06 plus the ability to buy factory ammo if necessary.
To me it comes down to the 35 Whelen or 9.3x62, if you are a heavy bullet type of guy then the 9.3x62 is the one you want. For running 200-250's then the Whelen is the one you want. I realise you can get light bullets for the 9.3x62 and heavy bullets for the 35 Whelen but I'm just talking in general terms. I had my Whelen built with a 1 in 12 twist so I could shoot the heavy bullets but in the end decided that for a heavy bullet 250's are more than enough for anything here. I will say the 275 gr Woodleigh is an impressive bullet and was accurate.
The 35 Whelen shoots a bit flatter with something like a 225 gr Accubond and is excellent on game but the 9.3x62 with it's long heavy bullets would be a hammer. Like someone said earlier it would be like comparing a 270 Winchester to a 280 Remington, there are differences but in the real world there is no difference on how well the work on game. Unlike the 338-06 you can find ammo for the 35 Whelen and 9.3x62 if you ever needed to.
