If you attended a lot of IPSC matches back in the days when shooters hot rodded the .38 super you saw this happen a lot.
Its scary but its not that big of a deal.
Usually its caused by a case head seperation like the quicker fellow said.
Those in turn are often caused by weak brass, overcharged casings, or insufficient chamber support or sometimes a combinatoin of the three.
Its more prone to happen with a .38 super in a 1911, but it has also been known to happen to .40 Glocks.
Its scary but its not that big of a deal.
Usually its caused by a case head seperation like the quicker fellow said.
Those in turn are often caused by weak brass, overcharged casings, or insufficient chamber support or sometimes a combinatoin of the three.
Its more prone to happen with a .38 super in a 1911, but it has also been known to happen to .40 Glocks.