Abstract: A drive device for the breech mechanism of a gun comprises driving and driven members connected to first and second elements, respectively wherein one of the elements is movable with respect to the other. The driven and driving members are separable as the elements move apart and re-engage as the elements come together. The connections between the members and elements permit the driving and driven members to execute a rotary motion about a common axis when the members are engaged together whereby energy is transferred from the driving member to the driven member.

Abstract: A drive device comprises driving and driven members, and first and second elements, one of the elements being movable with respect to the other. Energy derived from the coming together of the elements is stored, preferably hydraulically, and transferred to the driving member. Advantageously, the drive device is applied to a gun whereby the device may be used to drive the breech opening and closing mechanism and/or the loading tray. The first and second elements include the beating plate and a part of the breech structure. Energy to be stored and transferred is obtained from the recuperation of the gun after firing.