I have been reloading .223 Rem for years, nothing particularly hot, just nice, accurate 100yd stuff with 69 gr bullets. Always checked for split case mouths and a cursory look over before primer/powder/bullet. I recently had a case head separation which certainly got my attention. I bought a machinist-type magnifier/light and have started really checking my brass. Split case mouths are easy to spot but my criteria is to pitch any case that shows any sort of ring around the case, no matter how faint or partial. Not bothering with the usual small scratches or tiny dings but any circumferential mark is out. I also made a little pick-like probe and drag that along the inside of the case to hopefully catch any crack developing from the inside. Does this make sense or is it overkill? Enough shooters at my club fail to pick up their brass so range brass in .223 is plentiful and cost is not an issue.