As 25-20 said, it most likely is due to an over sized firing pin hole. As to the guy with the Remington, maybe it was a decade ago, a fellow at the range had an new Remington M700 that was showing primer cupping around the firing pin hole. He claimed he talked to the factory and that it was deliberate, that is Remington made the firing pin hole large so the primer would cup around the firing pin, and make a better gas block! Hey, could be.
Auto pistols and auto guns are very hard to diagnose in terms of over pressure. Unlike manually operated arms, where you will feel sticky extraction, these things open up on their own. Primers are only a reliable guide to high pressure when they blow, or pierce. And if they do that, you are way over maximum pressure. Just this week I was shooting my JC Model 50 in 30-06 and every one of the loads blew, or had gas leak around the primer, and all of the cases had expanded primer pockets. And yet, no primer cupping! While the primer edges looked flattened, but not perfectly flat, the firing pin indentation looked normal. However, the blown primers were a clue something was wrong.
For an auto pistol, if you pistol extracts and feeds normally, your ammunition is probably safe pressure wise. Over pressure ammunition will over accelerate the mechanism and you will have unusual function problems. A typical one is an over ride where the slide closes on an empty. The slide was accelerated so fast that the next round in the stack was not picked up. Might have stove pipes, or cartridge jammed on the feed ramp. With my 1911's, the ejection distance gets to be around 20 feet. I much prefer the brass falling within bending distance, not walking distance.
Those fun loving guys at AMERC pushed out a lot of junk ammunition, and got rich doing it! You can see the after effects of overpressure
This is a picture of the AMERC cartridge which caused this mess. Excessive pressure caused the unsupported part of the case head to deform. The one which the sidewall ruptured caused all the breakage. I want to make the point, the cartridge case is a gas seal. It is not a structural element, it is not there to carry load. It is infact, very weak. The locking mechanism, barrel, chamber, are all there to support the case. A cartridge case cannot hold all the pressure by itself, and the unsupported areas will rupture given enough pressure.
Clearly overpressure cartridges. This first is a 9mm
Another example