Good one BR!  When I reloaded the now once fired BCC cases, I was having a problem with some of the little balls getting wedged between bullet and neck and forming a bump.  The now better formed to the chamber brass has a bit more room in it, which makes for less compression of the charge than the new brass.  The bumps weren't occurring with the shiny new cases.   Cleaning the inside of the neck with a brass brush seemed to have solved the problem.  I have a couple more jacks I got from a scrapyard when I noted they didn't have as much play in them as the one I now use.  Someday....