I have a 35 whelen and I am very fond of it and shoot it a bit but have never killed game with it. I would not put a muzzle brake on it. I also have a 338-06 that does a great job on deer and the one elk I have killed with it.
I love both of those cartridges but if I already had a 338 win mag I would do like "Rossimp" said above and down load it a little for the times I new I would be hunting where extreme long range is not needed, say out to 300 - 350 yards. By getting the load down to about 338-06 velocity you will have a fairly flat shooting load that will go to 350 yards just find and you get to use a rifle you are familiar with in the process. You may find a load that would group well enough to your magnum load to use the same zero or a least group with the same windage to the point you would just need two drop charts and could carry the two loads with you on a hunt to cover all bases.
With all that said if you must have a new gun just get a 30-06.
