Volume for smokeless - I recall an article from way back (1970's or earlier) by Elmer Keith - he went with volume over weight - was convinced that powder changed weight from changes in moisture, etc. - he found his most reliable loading was by volume, so discussion was about the most accurate volume dispensers that were available, then.
Yes, and Keith saying the weight of powder changing is probably a fact as well.
But for probably <1% of reloaders, they will take any tiny bit of improved consistency/grouping they can get. Factories are not loading ammunition to the precision of the accuracy guys, meaning they don't turn necks, true primer pockets, etc. There is more variance in the rifles it will be used in, the lot of cases going through the machinery, the lot of powder, primers, wear on machines, etc.
You have the F-Classers prominent in competition and social media like Eric Cortina, who makes a pretty entertaining and informational video, and then there's the best benchresters today, etc.
My guess would be whatever game the best are in, with the money they spend on rifles, scopes, travel, etc, if experimenting showed volume charging gave tighter groups and more consistent performance, they'd do it. Alternately, if they had to pay attention to being perfectly consistent in technique from thrown charge to thrown charge to just get the same results, then they're probably going to go with a really expensive digital scale where the consistent technique necessary is pushing a button.
Any benchresters here? Most still charging by volume; or have they made the move to spendy electronic scales as well to chase tighter groups?
At that level of competition and at that level of being financially invested in it, I'd assume that whatever means of charging proved to deliver better grouping ability, that's the one they'd be using.
That isn't the other 99% of reloaders out there.
