Originally Posted by Bindernut
Different brands of cases will vary in internal capacity, neck wall thickness and ductility of the brass (causing differing neck tension).
You might want to check into segregating your brass by brand if you're looking at another step towards making more consistent ammo.
I'm just finding out how much inconsistency there is in the brass. I weighed 50 unsorted cases that were deprimed before cleaning and 50 that were deprimed after cleaning. The range of weights for brass that was deprimed before cleaning was 7.3 grains (highest weight - lowest weight). The range for cases that were deprimed after cleaning was 9.6 grains. So depriming before cleaning does reduce the variability some what, but the real variability is in the cases themselves.
I was surprised to see just how much the weight varies from case to case. Especially considering that 9mm cases are not very big.
I am now in the process of separating the cases by head stamp. I will determine the weight variation by brand to see if it is really worth the time and trouble to separate them before loading.
I have also measured case length and wall thickness and find about the same variation in unsorted as in cases sorted by head stamp. I could not find any real statistical difference between the sorted and unsorted groups. They all varied more than I expected.