@Mikecr When using Quickload ( I assume you use this) what case volume do you use in the program, the fired non resized case or the fired resized case.
I fire form cases 3 times without body sizing for measure of H2Ocapacity. This is also a point where I decide about case trimming/trim length.
Late stage case preps & sorting for me.
I do not go into powder development until past this stage.
BUT:
I don't FL size cases -ever.
So my capacities hold as my brass lasts a very long time, with no further trimming or loosening of pockets.
It doesn't just happen that way. There are a lot of choices leading to that.
Where you do heavy body sizing, which leads to continued trimming, and case hardening that changes it's character, then effective capacity changes.
You're led to that by cartridge design, but if your chamber is loose as well then it's amplified to primer pocket loosening and cycles of case replacement.
This common scenario makes capacity matching a futile endeavor. I wouldn't bother with it there.
Instead, I would seek a forgiving enough powder load.
For QuickLoad I'm initially forced to guess the formed outcome. That's all we can do.
But I'm pretty good at it, consistently predicting within a grain H2O capacity of fully formed.
I measure all dimensions, including neck thickness, for 10 new cases in lot. I pluck the mean of them and measure it's H2O capacity.
Then I build this case in 'Cartridge Design' (sub program inside RCBS.Load), adjusting web height and thickness taper to match capacity.
Then I consider the chamber clearances and re-scale the case to [-1/2thou] of chamber, everywhere.
With that I get a predicted formed capacity that I initially use in QuickLoad.