And I quote, "I think early on the rim was enlarged from microscopic to miniscule". Unspellable, that's GOTTA be a significant improvement! (grin). BTW, how about that undercut on the newer cases, you know, just above the rim? Does it help with extraction?.........what is the purpose of it? And it's on ALL revolver cartridge cases, not just .45 Colt. I'm wondering, JD45