Never tried Bergers due to the extreme freebore in the wby. I here Bergers are very secant o-give, vs. tangent o-give like an accubond, thus the bergers are very finniky for seating depth and acubonds arent.
Im not sure how you could adjust them. I guess they would shoot good or they wouldnt and there wouldnt be much you could do with it at that point.
Hang in there, Im sure somebody here has tried and has been successfull launching Bergers from a 300wby.