I just looked at some good cases (45 ACP) that I picked up in the same spot that day. They all have small "bright" areas to both sides of the firing pin strikes. A couple of those cases were nickel plated Hornady and have about the same amount of tarnishing on them - been there on the ground awhile. Do you think a 1911 .45 extractor would "catch" and hold on a .40 case like you described? Thanks! - Bob