You can load it to whatever you'd like. US specs are something like 35,000PSI SAAMI with a .321" bullet.

What calibre was it to start with? The 6.5x55 is a Euro CIP 55,000psi number and the 7x57 Mauser is the same as an 8x57- ie: 57,00psi, also the same as the 9.3x62.

That's .32 SPL size. The US ammo or RP and WW today about matches 20" .32 SPL M94 lever gun speeds of around 2,150fps to 2,250fps with 170gr. bullets - according to those who actually chronographed them. Both make pretty good deer or small black bear loads.

I would load it to normal Euro CIP data strength - ie: 57,000psi as-in Norma factory levels.