I would be surprised if there is any significant difference between J and JS loading data unless exceptions are made for older weaker actions/condition. Loading data for other than the original 196gr. bullets may be more scarce for the .318 version, as well. Any data for American 8x57 Mauser lighter bullets will almost certainly suffice, since loads are kept consistently mild to prevent .323 projectiles from being fired in .318 bores. Someone may prove me wrong, but I am basing it off formulations for 8x57JR in European brands. 318 diameter bullets can be gotten from many sources. I have Woodleigh, and Hawk in just the bullets, and in rimmed version, loaded ammo from S&B, RWS, and Norma, which as mentioned are loaded hotter than American brands in .323 diameter rounds.
Norma probably has brass, as well, even if it is new old stock. You can certainly neck size downward with 8x57JS brass, but headstamps will then be wrong.
Surely there will be information listed online just by typing in 8x57J, from various sources.
Yamoon and other 8x57 fans will surely chime in soon.
I would have jumped on the rifle you purchased myself, if it was affordable! Sounds like a peach.
