Only because the sniper only use what they are given, chamber the rifle in the Wby or the 338 RUM and you would get the same kill results.
The 338 Lapua was designed from the ground up as a military cartridge and was based on the 416 Rigby case. The 416 Rigby case was used instead of the 378 cased to get away from the belt. The 378 is based off of the 416 Rigby with a belt added
History Of The 338 Lapua As Told By Lapua 
