I have fought runout like everyone. I finally have it down to less than a thou pretty consistently measured on the bullet ogive.
Whether it makes that much diif or not is debatable unless you are a master at reading wind. However my philosophy is to make my rounds as uniform as possible no matter what. OCD is guess!
I only think about controlling runout after the first fireforming of cases matched to my rifle. I never use an expander ball. I triple seat my bullets. And I never neck turn to try to control runout - that dosent work because the case and neck are out of alignment to start with. I only neck turn to shave high spots if they are over min avg thickness by more than .001. If a neck has a thin spot i save it for annealing setup or plinking. But most variances tend to be on the outside - too thick in spots.
I use bushing dies with a co-ax. For some reason ( spring back?) neither a bushing or conventional f/l die seems to sufficiently align the case neck to case body on new brass that has excessive neck runout. Only fireforming will for me at least.
