It usually occurs when the shooter fires a semi-automatic pistol with a limp wrist, causing the muzzle to rise excessively. As a result, the spent case is not totally ejected and the spent cartridge gets caught by the slide slamming home. However with the DE it's a design flaw.
The end result is a shell case that sticks out of the chamber like a stove pipe.
See below:
The end result is a shell case that sticks out of the chamber like a stove pipe.
See below: