Quick PSA that shouldn't need to be said, but I'm gonna say it anyways and hope it helps other guys not repeat my mistake. When your measuring brass dimensions with calipers, make sure they are bare. Assuming flat surfaces like the Hornady comparator and comparator base will yield the same measurement is wrong. They have their time and place for specific tests, but not for everything. I made this mistake over the last couple days while measuring the outside neck diameter of necked down brass. This user error overly complicated an issue and wasted some good folks time. It also exposed another learning opportunity for new reloaders, and I want to give a big shout out to @wind gypsy for the free advice, patience, and expertise, while I worked this out.