How a battleship's main battery was fired electrically

How did main-battery guns normally ignite their propellant charges?

Under the cited 1945 procedure, closing the firing key completed an electrical circuit that ignited the charge.

A Naval History and Heritage Command manual traces the sequence from manning the battery and starting hydraulic motors to the director's firing warning. Closing the key energizes the circuit and sets off the propellant. The mechanical work of loading and training a gun remained distinct from the electrical act that initiated the shot.