I have tested both Remington and Federal hunting loads, and they are severely underloaded for a proper 8x57JS (.323" bore) rifle. Chronographed muzzle velocity was in the range of 2300-2400 fps for a 170gr bullet.
I know that S&B makes full-power 196gr loads for this cartridge, but they are FMJ and not suitable for hunting. (They actually have a steel-jacket.) The MV for these is about 2550 fps out of a Yugo surplus M48A.
Handloading is probably the way to go. Here are the companies I know make bullets for 8mm:
Hornady: 125gr SP, 150gr SP, 170gr RN, 220gr SP
Nosler: 180gr Ballistic Tip, 200gr Partition
Sierra: 150gr SP, 175gr SP, 220gr SPBT
Speer: 150gr SP, 170gr SP, 200gr SP
Since full-power 8mm will push a 150gr bullet at or beyond 3000fps, I usually download to .308 velocities: 2700fps, just to make it easier on my shoulder.
-z