I have no direct experience with either the Browning BAR Stalker or the 300 WSM but I do have a fair bit of experience with loading the mono-metal bullets. Admittedly the mono bullets are not my favorite 308 caliber bullets but I sometimes use the 168 grain pill in a 30-06 or 300 WM. They really like being seated well away from the lands to shoot well. You might have an accuracy problem If you are not seating them .05" to .10" off, maybe more.