Another Glock goes KaBoom! This time it was a 10mm.
If your semi auto starts to eject empty shells that have a bulge like this, stop shooting!
That bulge means that the cartridge is about to blow, and it will only be a matter of time before that happens and you ruin your gun and perhaps need a trip to the ER. Glocks are notorious for this, especially in the .40 S&W round, because the case is unsupported by the barrel in that area.