A ARFCOMer noticed the spent cases from his 1994-vintage Glock 20 (10mm Auto) appeared to be very close to failing (see case photo below). The problem seems to be that the rounds were not sufficiently supported by the chamber. A replacement factory barrel gave the cases a lot more support. He decided to do some tests at the range with his old barrel … you know where this story is going … the second round caused a catastrophic failure. The magazine and part of the frame were blown out. Fortunately he only suffered very a very minor injury.
The moral of the story is not to shoot guns that are known to be unsafe. If you have to, construct a rig that allows you to remotely fire the gun from behind cover.
[ Many thanks to jdun1911 for emailing me the link. ]