the 10,75x63 comes frome the past, the 10,75x68 is something that goes the same way it seems. when it happen like kuduae find out the 10,75x63 from austria was reworked & extended in the mauser factory very quickly. I see the only reason for this development that the people at mauser were seeing the biggest cartridge working in a standard action in the 10,75x68.
maybe its not the cartridge for elephant, buffalo, lion but up to medium range it work on smaller game.