These are not myths, these are facts. Any time you have a case failure you run the risk of a catastrophic failure to the gun. At the very least the gases venting into the frame will usually damage the ejector and blow the magazine out the magazine well, damage will also usually occur in the trigger Assembly. This can and does happen to many makes if the case is not supported correctly. When you are dealing with pressures of 20,000 psi(standard 45 acp is around 21,000 psi) or higher amazing amounts of damage can be done.
As for design changes in the glock, all you need to do is look at the chamber end of the earlier glock .45 barrel and compare it to a current manufacture .45 barrel, you will find that the case is much better supported in the current barrel. Now that may constitute a design change in your mind, but it most definitely does in mine.
These are not myths, these are facts. Any time you have a case failure you run the risk of a catastrophic failure to the gun.Again, this is incorrect. A case failure will send gases down the mag well and usually blow the mag out. If any damage is done, it is usually to the mag and mag catch.
A catastrophic failure would be one in which the barrel is split, frame is damage and the pistol is ruined. These have happened to any number of different pistols, H&K, Glock, Ruger... These are always the result of severely over pressured ammo.
Proof of this can be seen in the FACT that H&K pistol have much better supported chambers than do Glocks. And yet they have still had major KB's in them.
It is the ammo, not the pistol.