Scores are no better or worse at 300-1000 yards with cleaned or dirty primer pockets. Rifle shoots 1/2-3/4 MOA elevation (I'm shooting irons with a sling, not rested). I have done lots of testing, cleaned Vs dirty primer pocket and or brass. Dirty brass shoots just as well as shiney brass and dirty primer pockets shoot just as well a clean ones.
I know guys that are anal enough to weigh and sort primers. Does that really matter? To them it does. I weigh and sort my brass into 1 gr lots, to me that matters. Some guys use .5 gr lots, to them it matters. I guess it all depends on the game you are making the ammo for and what you think really matters. It is all part of the mental game. If you think is matters that the primer pockets are clean, do it.