It'll kill as far away as you can hit with it. The trajectory is such that 400 yds is probably the outer limit for hitting. I have a Griffin & Howe Model 70 in .338 and the guy who commissioned it had the drop at 200, 300, 400, and 500 yds engraved on the floorplate. For 200, 300, and 400 it lists the drop in inches beneath the yardage. Under 500, it says simply "no":) i guess the figures were based on the 225 grain factory load.

Anyway, if you're shooting at the critters this cartridge was made for, you'll probably be a lot closer than 400 yards.