I'm shooting the 200gr NAB with rl26 and Cci large rifle mag primers. SD of 6 and keeping well under .5. Was hoping for a little more speed but am sitting at 2810 with a 25 inch brux 10twist. Can't remember the exact charge weight and I'm at work but can try to check it tomorrow. Also, only seating to saami spec so I can feed from the magazine.
The 200 AB is a little bit on the long side for the wsm. You didn't ask, but may I suggest the 180 AB. I think this is where the wsm shines. After extensive efforts to get a Browning a-bolt to shoot, I finally found a load.
65.2 gr imr 4831
.012" off the lands
LR primer (federal 210m)
lands start at 2.2895". This load shoots 1" or less at 220 yards.
For what it’s worth. Loaded for pressure today with the tikka. Stopped at the first sign of extractor marks. Primers starting to go flat but corners still round. Hit 3018 with 66gr of rl16. Pleasantly surprised for sure. Loaded 65, 65.5, and 66. It has to slow down or go faster so going back to load 64 and 64.5. Take the best and fiddle with seating depth. Worse group was 1.25. Should hopefully be in the low mid 2900’s. used a magneto speed for the chrono. Against fwiw.