In the 338 Allen Xpress which will drive them from 2900 to 3000 fps they perform extremely well in a window from 400 and out to about as far as you can hit your target.
In my 338 Allen Magnum with its 3300 fps muzzle velocity, range really needs to be out past 1/2 mile but past that they work extremely well from there out to much farther then I can shoot at game!!!
My 338 Raptor is right between these two mentioned so I would estimate it would be best to be at +500 yard on heavier big game.
These recommendations are for big game in the 500 lb. class or heavier. For deer size targets, these bullets will get the job done at pretty much any range but at closer range, expansion will be significant and tissue damage quite severe with the elite hunter. Inside 300 yards, things can get pretty nasty!!!