It's a real phenomenon that a rifle can occasionally shoot tighter groups (in terms of angular dispersion) at longer ranges than shorter, but it's not due to the bullet "settling down" or "going to sleep" as is commonly claimed, more likely to be related to mental state of shooter, parallax issues or similar.
You can read this or just take my word for it
Also you could try a greater range of seating depth than the .015" difference you've tried so far with the 140gr. No idea about the velocity spread.
See how those 130gr Bergers go.
Bookmarks