I've witness several KaBooms, 2 involved both a S&W99 and a Walther 99 in forty. Both were firing factory ammo, 1 Federal and 1 Remington and required new frames. I believe both of these guns actually fired out of battery, but that is just my guess. Another was a 10mm Glock and he was doing the big no-no, shooting lead till he chambered it down to a 9mm, that caused him some hand burns and got him a new frame and a nasty letter. The thing is there are many factors that come in to play, but it is caused from TOO much pressure for the gun to handle. It is just bound to show up more offen the higher pressure cartridges to start with like the 40 and 10.