Abstract: A fire control system for a gun comprises a means 10 for determining the position of a target, computer 14 which receives signals representative of the target position from the means 10 and computes fire control signals according to a known programme, the fire control signals being transmitted to a gun drive mechanism 16. The means 10 includes an optical sighting device 11 containing a visual display 30 on which two images are presented in superimposition. One of the images is of the field of view containing the target while the other image is a pattern of predetermined character which is controllably movable over the visual display by adjustment devices 32A, 32B under control of the operator. The means 10 further includes a ranging device 12 and a manually controllable element 21 for altering the field of view. The arrangement is such that a target is located within the field of view as a result of adjustment of the element 21 for altering the field of view.