Quote:
Originally Posted by Forester
I'm fairly sure that work hardening requires actual "work" as in moving metal around. I don't think scrubbing all the "other than brass" off the outside of a case is moving any metal around.
Nope - tumbling brass actually "works" the brass and moves metal around. You are not thinking about the other pieces of brass that hit a given piece of brass 100's of times a minute. A zillion small hits equals a few big hits.
It does alter neck dimensions and harden brass - if you don't believe if, FL size some good brass and sit 50 pieces in your tumbler for 8-12 hours then seat bullets and compare that with a piece that wasn't tumbled.
Really ran into this when I was a newb and thought shiny was better - I had some milsurp 30-06 that had annealing "stains" on neck and shoulder. Tumbled them long enough to get that off - reduced neck diameter and made the brass HARD.