The Porter Revolving Turret Rifle was an experimental firearm from the 1850s. P.W. Porter designed it to fill a demand for repeating rifles during the percussion cap era. It featured multiple chambers that could be cycled vertically before the user needed to reload.
There was a significant design flaw. Chain fire--that is, sparking between chambers--could cause multiple chambers to discharge simultaneously. One of those chambers is pointed at the user's face.