Oscillations of light wheeled vehicle’s centre of gravity, caused by firing weapon integrated on it, are studied through simulation of its axial and angular displacements. Dynamical model of system with three degrees of freedom is used and mathematical model of oscillations is defined using the Lagrange’s equations of second order. Weapon recoil force and resistance force that causes vehicle’s oscillations is calculated according to the internal ballistics data of integrated weapon and chosen system construction. System of differential equations is numerically solved in MATLAB for real firing conditions and vehicle configuration. Coordinates of weapon mount and elevation and azimuth angles are varied and results are analyzed.