Thanks guys.
Will give those suggestions a try.
To be clear -- I am using 2 types of brass. Winchester and Hornady. But they are separated for load development. I.e. same brass for a given load.

I do use the h4831sc for my winmag and I agree that it is a great powder. But there are no loads for 150 grain bullets using h4831sc. 150 would be my preferred bullet weight -- but I may just go with 180s as they do group much better.

I have been reloading for about 6 years. But am always willing to learn new tricks. This is my only rifle that gives me fits in the in the accuracy department. It is quickly becoming my white whale...