TX Hunter. It sounds like you are making some good choices in components. I shoot an accurized 300 WM that still wears the Remington factory barrel. The inconsistency in some of the brass I used drove me crazy. Last year, I switched to Norma brass and it was a night and day difference.
One thing I read about new brass was to round up the mouths and measure them for uniformity. The closer the uniformity, the better. Some of the cheaper brass varied in case mouth thickness by .004 to .005. The Norma was for the most part .001-.002 in uniformity. I kept all of these and threw out anything that was .003 or larger. But, with 145 pieces of brass, I only threw out 5 of them. I think that says a lot for their brass. Sinclair makes a good tool to measure this for about $70.
I am pretty new to the long range scene myself. My goal this year was to shoot 700 yds. However, with a lot of reading, Shawn Carlocks video, and some time on this website, I am hitting 1025 yds consistently. That's on a calm day anyway. I still have a lot of work to do with reading the wind and some other variables.
A couple things I would recommend is the above mentioned video, a good ballistic program (I use exbal), and a book titled Handloading for competition by Glen Zedicker.
Hope this helps. Good luck!
