Re: H870 or H1000 Loads for 65x284 ?
H4831SC under the 140s is an amazing combo for sure. As far as I'm concerned there's only one primer for that combo. Remington 9-1/2. It's the only one I found that would get me in the magical single digit extreme spread range. 210Ms got me there with H4350 but not with 4831.
Long range shooting is a process that ends with a result. Once you start to focus on the result (how bad your last shot was, how big the group is going to be, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.