8mm-06,
As much as I like the 338-06, I don' t think that you would be gaining much over your 8mm-06. IMO the 338-06 is at it' s best with bullets in the 200-225gr range and that is what you have have with your 8mm-06. There is more bullet selection available in 338 than 8mm but if you already have a bullet or two that works for you then that advantage is a moot point.

Quilly,
The only reason that I can think of that the 338-06 or 8mm-06 is not made by the large companys is due to low sales numbers. The 35 Whelan didn' t do very well when it was offered by Remington a few years ago. The 338-06,8mm-06 and 35 Whelan are normally used by people that have their own opinions, as opposed to the marketing department, as to what works on big game. The ballistic numbers on any of these three rounds are not flashy enough to catch the interest of the hunter who only spends two or three days a years in the field.