If you look at the original specifications for the two cartridges, they are more different than you might suppose. Part of the lack of recognition for that here in North America is the situation where even if a maker chambers a 7X57, they use the same barrels that they use (or would use) for a 7-08. In Europe you see makers and ammunition sellers continuing to supply a market that was originally for an intermediate length Mauser action and a barrel with a faster twist and slightly different chamber dimensions than is "normal" here for the 7mm rifles.
There is a lot more history in the 7X57 than many realize. I have an EF Heym commercial Mauser rifle that was originally a 7X57 that seems to call out to be restored to that chambering.
jim
