The Nickel cases I see split the most are .357 Mag and .44 Mag... / yes, they split at the case mouth. ( But I see a few in 9mm and once in a while in .45 acp split at case mouth too ) - but for semi-auto calibers, I sweep up floor at my local indoor range, and clean and reload whatever ends up in my lane...no way to tell how many times they've been loaded.
In .357 Mag and .44 Mag...I'm careful to make sure I'm picking up all my own cases.../ ...and sure, if I had to guess, they may have been loaded 50 or more times - maybe a lot more, I don't count either....but when I start to see a few crack, I seem to get a lot of them cracking ( which makes sense). Every now and then I will see a brass case crack as well ...but not nearly as often.
I'm not overbelling them .../ I bell just enough to set the bullet on station 4 so it doesn't fall out. Yes, I do load them toward the top end of the published recipe..but not at the max / Hodgdon TiteGroup in both revolver calibers / 158gr JHP Montana Gold in .357 and 240gr JSP Montana Gold in .44....
Every now and then I see someone renting revolvers at my local range...and tossing out their .357 Mag brass, so I'm usually hanging around and offer them a few bucks per box, if they will just keep them and let me have them. I had a guy the other day refuse my $ 5 ...and he gave me the brass anyway - which I appreciated.
My memory is about as sharp ...as a chewed up axe blade...so maybe some of those nickel cases are way older than I think they are...( I've been reloading for 50+ yrs.../ and I've been dragging some of that stuff around with me for a long time )...
