Sling,

I've reloaded for two 8mm Mausers. I also noticed having to work thru more different powders to get a good velocity than the other cartridges I've reloaded! I'm still not sure why, maybe its just that so many powders will work in the 8x57.

Anyway, Never did hit 2,600 fps w/ a 200 in 23" barrels.
But am satisfied with these:
2,500 fps w/ 200 Speer HCs and 200 NPTs using H4895.
2,700 fps w/ 185 Rem CLs using IMR-4064.

Both rifles like both those loads accurately.