As Marseille mentioned, the 6.5x57R is normally loaded a little softer because in Europe it's normally chambered in break-action firearms.
I don't know if that's actually needed, but it isn't a bad idea, especially with older rifles. My own 6.5x57R is a Sauer drilling (over 16-gauge barrels) made in 1958, and would no doubt easily withstand standard 6.5x57 loads. But there's no reason to, as 100 fps doesn't attain any significant difference in trajectory or "killing power" in such a firearm.
Both the 6.5x57's are wonderful rounds: light recoiling and accurate, with plenty of killing power--as long as we put the bullet in the right place. I wouldn't hesitate to use mine on elk with the right bullet.
