Non-centroid vibration of rifle gun and containment measures

Even if a rifle's center of mass and recoil point are aligned, it will still exhibit vertical movement. Today's firearms are all driven by a piston. If the piston is located above, there is force and torque acting upward. If located below, there is force and torque present. Based on the data, it can be calculated that the rotational speed of the bullet is 24347.34rad/s, which is 3876.9 cycles per second. The un-centroid motion comes, with either an upward or downward motion-un-centroid vibration. The muzzle vibration rule at vertical direction during launching process is captured using photography equipment, and the correctness of model are verified by comparing measured data and numerical results. The dual piston structure, which leads to a symmetrical trust of up and down, can reduce asymmetric forces.