Wynne, I think that the lack of response is a combination of things. It is the way it is; and I believe that will change with time.
You mentioned un fired Lapua cases having a little more seating tension than you are used to having. I read that many good shooters run a neck turner mandrel thru their case necks as the last step before primer, powder and bullet seating. I tried this technique on some new Lapua brass, and the bullet seating was smoother, and very consistent feeling.
I don’t hold’em well enough to tell if makes a difference in accuracy; hence my question.