"This is done by working up loads properly, for the individual rifle, not from choosing an arbitrary velocity value."
Working up loads properly with a 7X57 is done by watching the velocity.
Velocity will tell you if you're getting too hot.
7X57's are all over the map as far as throat goes. For example, it may take anywhere from 46 to 52 grains of H-4350 for a 145 grn bullet to reach 2800-2850 fps just because the throats are so different from gun to gun.
YMMV
