We suggest and investigate the performance of a new design of a recoiling mortar system with the purpose of the mortar to be mounted on tracked/wheeled vehicles. Mounting of gun system on tracked/wheeled vehicles increases the gun mobility, efficiency and maneuverability. The potential outcome of the new design suggested in this paper is to reduce recoil force of the conventional 120-mm Russian mortar by the adoption of a recoiling-barrel mortar system rather than the fixed-barrel system currently existing in The Egyptian Armed Forces and many other armies all over the world. The maximum total recoil force in the mortar design suggested in this paper is predicted to be reduced by more than 75% compared to that in the traditional fixed-barrel mortar system.