I believe I had an "A ha!" moment today. It was also a moment that confirms (I think) why we do what we do with regards to being thoughtful and careful. I load .223 only for plinking out of my AR. 99% of the time I'm loading 55gr FMJs. Normally I've been using brass that I *know* is once fired (or low firings) because it came from me or it came from my buds (who don't reload). I've set up my die to only bump the shoulder back a little - so I know cases coming out of my gun aren't getting stretched a whole lot when they're sized. And I don't shoot hot loads. So I haven't (rightly or wrongly) been too too concerned about incipient case head separation. I'd look for signs on the outside.....and occasionally scrape around on the inside. Over the last year I've picked up a BUNCH of brass that I have no knowledge of its history. So more recently in my case prep I'm been very studious about checking the inside of every case with a pick to see if I can feel any brass anomalies. I can't say how many cases I've checked this way. I've never rejected a case......until today. The internal scraping process had produced no "positives" - and I was really wondering about its value. But today, on one case, I noticed the pick was encountering a good amount of unevenness down by the web. I thought "You know....this very well could be what it feels like. It's not worth risking it. This is getting tossed." Then I thought "If I understand this all correctly (case head separation and how and why it happens) there's a good chance this case will be quite long. I measured it: 1.786". I think this is the longest .223 case I've ever had. (For those that don't load .223 - this measurement is .026" longer than the *max case length*!) I then thought it would be fun to cut open the case and see if I could confirm wall thinning. I have to say I don't think I can actually see it. You can see in the photo the areas that were causing the pick to scrape and get caught up. The bottom line: I'm now a firm believer in checking the internals of the case for brass anomalies.