My favorite case, the case that has been fired in a trashy old chamber.
“All have been fired once (three point crimped primers still in place) most probably in the Hellenic Army's M1919 Browning machine guns” Again. I measure the length of the case from the head of the case to the shoulder/datum first, if the cases I am sizing have been fired in a trashy old chamber I want to know, BECAUSE, I off set the length of my chambers with long cases with added length between the head of the case and shoulder, nothing magic about sizing a case to length, moving the shoulder forward is the most time consuming, fire formers are required to chamber a round and pull the trigger AT THE FIRING RANGE, I find cases with the shoulder blown forward, not a specialty, I size machine gun fired brass, I am a case former, I have forming dies, forming dies are used to form cases from a parent case to smaller cases. 30/06 to 308 W for example, then there should be a question as in ‘Why did the manufacturers make a 30/06 forming die”? the 30/06 is the parent case, it works when sizing machine gun fired cases and cases that have an abundance of resistance to sizing. The forming die doubles as a trim die also.
R-P made cylinder brass, a 35 Whelen/30/06 type case with straight wall and 2.650 long, I have no clue how a reloader could fail when sizing cases to fit the chamber from the bolt face to the shoulder of the chamber.
Cylinder brass:to late for me, I will never get around to using up all my brass, before the cylinder brass was available I use 280 Remington cases, forming the 280 to 30/06 required erasing part of the shoulder and forming the new shoulder out of the case body, the shoulder of the 280 Remington is ahead of the 30/06 by .051”, again I have no clue how a reloader could/can miss when fitting a case to the chamber.