I do not have a definitive answer for you.....However, in Ken Waters Pet Loads, his write-up on the 416 Taylor cartridge has a C.O.L. of 3.325 inches with a round nose bullet........From that, you can extrapolate that the maximum OAL is in keeping with the "standard length action" of the 30-06 which is of course 3.340 inches......same as the .338 Win Mag cartridge, which is the basis for the larger caliber Taylor cartridges....
Hope this helps,
Rojogrande