Abstract: The current interest in mounting large calibre guns in light-weight vehicles has forced designers to re-examine conventional gun-mounting practice. It has been commonly accepted that stabilising an out-of-balance gun on a moving platform is very difficult, or impossible, to achieve. Using a simple Main Battle Tank (MBT) elevation model, a theoretical investigation is undertaken into the effect of not having the trunnion axis aligned with the centre of gravity of the elevating mass. The effect of varying amounts of out-of-balance on the angular motion of the gun and power requirements are examined and the improvements using main battle tank hull motion disturbance feedforward are investigated.