Ok, so first case head separations are not from over pressure, usually it is caused from setting the shoulder back too far which causes the case to stretch and thin just above the web. The 25-06 was an obvious overcharge. You dont "run them that hot".
The way it works is, under pressure things stretch. The chamber expands as well as the front ring of the receiver. The steel does not yield but the brass does. After the pressure drops the steel returns to original form while the brass does not. Thats why you get stiff bolt lift. Thats why when you run high pressures you cant rechamber a fired case. And yes, if you can neck size you are not running high pressure. Unless your forcing the bolt on tight cases.
I dont think I want any more of your reloading advice after reading you last post. Many in competition run over 70k psi routinely and no one blows case heads. Thats poor reloading technique, and dangerous to the people around you.
I'm pretty sure I know how guns, cartridges, ammunition, and metals work... I've also been reloading for many years, and my technique is just fine. You keep talking down to everyone, then try to explain things that are very common knowledge, as if other people don't know them, but then you say you take our reloading advice. So, which is it? Do you already know everything, or do you take our advice because you're still a novice?
Case/head separations CAN be caused by very large pressure spikes, causing the weak-point in the case to be exposed by separating there. They can also be caused by a chamber cut too deep/headspacing issue, and also from brass that was drawn with a thin web.
The .25-06 AI, I backed it down 1/2 a grain, and that's where I run them at. So yes, I DO run them nearly that hot.
You can take my advice or not, doesn't make a crap to me. I NEVER recommend anyone running the pressures I do, and have stated many times I run my rifles hard. And I very very rarely give out load data for that reason. So, while you're on kick explaining the general mechanics of reloading to people who already know how it works, I think it might be best for you to take one last bit of advice and keep learning. Nobody will ever know everything, I know I don't, and never will...But that doesn't stop me from continuously trying to learn all I can.