Reading the comments section in that article it is pointed out that somebody came up with the 9.3X57 based on the 8X57 and Bock lengthened the case to 62mm to get decent performance from the 9.3. Later he made it a true 375 H&H performer by going with the 64mm case.

What Spooner forgets/doesn't know is the 8X57 was the parent case for the 30-03/30-06. The US studied the 8X57 and used it's dimensions but lengthened for greater powder capacity and hence greater velocity.