As a side note...
Be aware that the various manufacturers of rifles chambered in 300 Weatherby use very different chamber throats and leades.... True Weatherby brand rifles have long throat... the main reason is to help with the full power loads of the various Weatherby chambered rifles.
While numerous other manufacturers have a much shorter throat.
The end result is.. the shorter throats "make" higher pressures then a long throat. So be careful when trying to load max. reloading manual loads.
ALWAYS start at the minimum charge weight.
What brand rifle is yours ?
This link might explain better then me...
http://snipershide.scout.com/forums/...herby-chambers