The Weatherby is loaded to a higher pressure and the freebore does take more powder to get there. I have a long throated 7RM and it loads about the same as the Weatherby. Also at times R22 had lot to lot variations up to 20% difference so I always check a couple sources and average them.

"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli