The purpose of this paper is to study the characteristics of recoil motion of a new suggested recoil system designed for the Russian 120- mm PM-38 mortar, rather than the conventional fixed-barrel mortar system. The new recoil system enables to reduce the total force imparted by the mortar system to the carriage, with the purpose of the mortar can be mounted on tracked/wheeled vehicles. The paper presents the suggestion of the new recoiling mortar system along with the discussion of the presentation of constructional considerations and constraints. The dynamic characteristics of recoil motion have been modelled with the aid of a new mathematical model that have been established using MATLAB software. As a result of the suggestion of the new recoiling mortar system, the maximum recoil resistance force is predicted to be reduced by more than 60% compared to that in the traditional fixed-barrel mortar system. In addition, the maximum recoil distance was predicted to be around 26 cm.