Good information. I should tape it to the loading bench.
The one point you quoted from Hatcher that I am not clear on is that shoulder shape has no affect on pressure. Maybe in regards to high or low pressure but I thought and you have stated that the 30 degree shoulder appears to produce more uniform pressure according to the ballistics labs.
The same on case shape, no difference, but then some claim a shorter powder column is more uniform.
Given the equipment of the time Hatcher could not report on shot to shot variation with the precision that a lab can today, and I wouldn't think he could have looked at a time-pressure curve for an individual shot at all.
The average pressure produced by two cases of the same capacity will be the same, but the other statistics may vary.
