double-action

[ duhb-uh l-ak-shuh n ]

/ ˈdʌb əlˈæk ʃən /

(of a firearm) requiring only one pull of the trigger to cock and fire it.

Origin of double-action

First recorded in 1850–55

The powerful, double-action pumps quickly ejected the water-ballast.

A Sub and a Submarine |Percy F. Westerman
It was a wall mill equipped with a glass-front metal hopper and employing a ratchet spring-lock nut and double-action grinders.

All About Coffee |William H. Ukers
It was a double-action apparatus, made entirely of bamboo, except the pistons, which were of feathers.

The Philippine Islands |John Foreman
One double-action folding machine will fold fifty sheets in a minute.

The Pictorial Press |Mason Jackson

That is, the hammer would have traveled back all the way, whether it was cocked or fired in a double-action manner.

Warren Commission (3 of 26): Hearings Vol. III (of 15) |The President's Commission on the Assassination of President Kennedy