Re: Long-term springback on sized necks?
I've noticed that pin gauging soft materials is not very repeatable, After the first time it is performed on brass. The gauge itself can enlarge diameters ( from slight interference to a slip fit), particularly when done by hand. Temperature: cold brass, warm pin and then the other way around can account for perhaps as much as .0005 in feel. other than slight oxidization as a friction modifier you still have really close to the same hole that you measured originally. The big culprit is doing it twice with a long interval between measurements and doing it by feel!