I have loaded 200 grain Sierra's and 200 grains Accubonds for my two 300 WSM guns. The data I used came from the Nosler #6 manual. They of course do not show Sierra bullet data but they list data for 200 and 220 grain Nosler bullets. I used this in loading the Sierra 200 grains. The powder that shows the highest velocity with the 200's is RL-22. Starting at 63.0 grains and working up to 67.0 as a max. They show that the most accurate load used 65.0 grains.Velocities ranged from 2810 with the starting load and 2944 with the max. This is out of a 26 in barrel. IMR-7828 was listed as the most accurate powder with 200 grain bullets.
IMR-7828 is shown as offering more velocity with the 220 grain Nosler bullets. Starting with 61.5 grains and working toward 65.5 grains. Velocities ranged from 2613 to 2762, with these loads.
The information about the 200 grain bullets can be found on the Nosler web site. They list different powders for the 220 grain bullets.
