Originally Posted by bill123
Isn't the case bigger after the first firing, so larger case capacity means less pressure? Also to measure chamber neck diameter, I've always just measured the neck of a fired case and added .001" for spring back.
This is what I have generally understood and gone by. Recently did some development on one of my rifles with once-fired brass, then loaded "new" brass the same (even measured weight of brass, neck dia. etc) to be as close to the load-developement brass as possible, but still-- got extra pressure!
I will soon see if it was in-fact because that was the new-brass (I'm going to clean & re-load to re-test..)
but am damn sure this above post has merit far as capacity/pressure goes toward new-brass. In my experience, new brass does have less capacity and show greater pressures