Glock wallows out the feed ramp to aid in flawless feed of the ammo.
This leaves part of the case unsupported by the chamber and could result in case blow out with a hot round.
I have seen this happens a few times.
The case blows out at the rim, but it doesnt kaboom the pistol.
Ummm, I have seen what happens when folks who roll their own or try to shoot a Glock on the cheap use exposed lead loads instead of FMJ ammo. The octagonal barrels tend to build lead residue extremely fast and that will raise chamber pressures at an almost geometric progression. I have seen such a buildup in a Glock lead to a catastrophic KA-BOOM resulting the trigger group blowing straight down and nearly removing the trigger finger of the shooter. I still enjoy shooting the Glock (but wouldn't own one again for other reasons), I just understand they have to be properly fed to offer consistent and safe results for the operator.