Where do you get that from? Ive been loading some of the same pistol brass for 30yrs. So worn you cannot even see the head stamp anymore and never had a case head separation. On the same note we had a gentleman shooting new PMC 9mm at the match last weekend that had two case mouth separations leaving a brass ring in the barrel.
I work in a business that is pretty dangerous and I have seen A LOT of people get hurt bad over the years, so I tend to take a conservative approach in weighing risk vs reward. Watching a guy turn his hand into shredded hamburger meat, and another guy break his spine on the same project changes your attitude towards risk and reward.
It has nothing to do with courage, it's just a policy matter - if I know something to be a significant risk, I will make up a personal reasonable policy rule about it, just so I don't have to think about it anymore.
Like for example, I had a ladder skate out from under me once. So now I have someone stand with their feet at the bottom of the ladder. Go ahead and call me a wussy, but cracking a few teeth on a ladder has a way of sobering people up. Everyone is a big hero until their teeth are broken.
There are two basic questions to ask about reloading:
1. Suppose that I pretend that brass cases do not have a service life and I pretend that they are ALL infinitely reloadable. What is the cost savings vs the potential harm?
2. Suppose that I acknoledge that brass cases can eventually fail. Okay, so what is the safe reloading count, given the complete lack of available data?
For question 1, it's irrelevant. Reloading saves so me much money that squeezing every single penny out of my brass is not important to me.
For question 2, here's what I came up with:
Back when I first started reloading, I was a big Garand fan I did a whole ton of Garand shooting. That brass is expensive AF, so I was really interested in how many times it can be safely used. And safety is a genuine concern, because 30-06 case failure can pop a Garand apart like a toy balloon.
Some types of rifles will "work" brass cases really hard, and it makes the brass brittle, and if you just keep reusing a case over and over, it will absolutely fail. Just like when you bend a coat hanger over and over again, it will eventually work-harden and snap. You can do stuff like re-annealing the case neck and shoulder to extend the life, but I never liked that idea because rifles generate 50,000 psi and that's a HUGE amount of energy.
So I gathered what data I could on case failures and I found that the worst of the "brass working" rifles and autoloading handguns could see head failure and splits in as low as 5 reloads. Sometimes the split doesn't vent any gas at all, sometimes it does something like blow the magazine out of the gun, sometimes it blows the gun up.
Some of the super-velocity small bore rifles will see case splits in as few as 3 reloads. They scour out their rifling fast too.
So to make things easy for myself, I just made a personal rule that I would use autoloader and rifle brass 5 times and then toss it.
You might say, "That's just a rule of thumb you came up with! You have no hard data to support that 5 round count for my UZI!" AND YOU ARE 100% CORRECT, AND THAT'S EXACTLY WHY I USE MY RULE OF THUMB. If there is no hard data available, given potential for severe harm, then the conservative approach is to GO ON THE LOW SIDE.
Note that I don't use this rule for revolvers. I could not find a single instance of case head failure in straight wall revolver ammo, and the mouth splits do not vent gas anywhere it shouldn't be. So I reload revolver brass until it dies.
Also, part of the above logic is the fact that I will use range brass pickups for pistol reloading. And who the AF knows what the pedigree on that stuff is? And it's free, so you lose literally nothing by throwing it out after 5 loads.
Also, I have about 40,000 9mm empties in two of those big home storage buckets, and I'm at the point now where it's not even worth it to me to pick it up.
That's my 2 cents on the topic, you maybe disagree, you may express that disagreement, you may call me a giant *ussy if it makes you happy, I do not care, it's all good.