At the range the last time I went, I heard "a regular" that is usually there on the same day I am, talking about how he would not reload the cases from that batch anymore.
I queried him for more info, and asked to look at the brass he was not going to reload.
It had a definite ring toward the base of the case that looked... defiantly thinner than I would reload. I mentioned that I was planning on only reloading 6 times per recommendations posted here I have read multiple times. He said that he knows people that have reloaded .223 20-24 times before not trusting brass for another reload. I asked him if it damages your chamber if you have a case-head separation during firing, and he said that the only real issue is that if you don't have a broken shell extractor, your rifle would be out of service for the remainder of your range session, until you got home to pull it out.
I am going to go with what he said... I have reloaded with Varget all the way to the top of the case (~27 grains), and compressed the load with no overpressure signs on the #41s that I could see. The "ring of resizing"
doesn't look bad at all yet (like it is getting thin), after like 6-7 reloads, so I will keep the once-fired collecting until I need them. I have a broken-shell extractor...
I have heard of resizing 9mm brass, but I have not seen the need, even after 10 reloads, and a co-worker never has resized his in the 10 years he has been reloading straight-walled pistol brass. He just chucks split-cases, and the any that "look unsafe".
My straight-walled pistol brass does not seem to have issues... yet with Unique and punchy loads.
I need to get a nut-wizard...