bellydeep,
Aside from the thinness of the barrel when rebored to .35, Nosler's data only gives 225's 2600 fps in the .338-06 because they only tried 4 powders, while their .35 Whelen 225-grain data includes 10 powders. Both Barnes and Hornady show 2700 for the .338-06 with 225's.
The Whelen's capable of about 3% more velocity when both rounds are loaded to the same pressure. Using the 225 AccuBond as an example in both rounds, loaded to 2700 in the .338-06 and 2800 in the .35 Whelen, the .33 caliber catches up in velocity at about 200 yards, and the gap widens beyond there. Oh, and the .338-06 kicks a little less, because the bullet isn't started as fast.
Elmer Keith noticed this longer-range advantage for .33 caliber bullets about 75 years ago, the reason he developed the .333 OKH and "quit" the .35 Whelen. This doesn't mean the .35 Whelen's a bad cartridge, just that muzzle velocity doesn't tell the entire story, especially when it's only from one source of loading data.
