A fire arm with improved salvo accuracy, having a barrel and a casing mounted on a supporting frame, whereby the frame comprises a cradle provided with a slide which can slide in a direction which is mainly parallel to the axis of the barrel. The casing is mounted on the slide of the cradle on a transversal hinge pin, and on the frame via at least one shoe mounted in a sliding guide provided in the frame. The sliding guide is inclined in relation to the direction of the axis of the barrel at rest.