Abstract: To study the wounding mechanism of rigid rifle bullets penetrating living tissues, ballistic gelatin was used as the tissue simulant and a simplified spatial ballistic model was established. The drag force, the lift force and the overturning moment were all considered to be functions of the attack angle and the velocity in the velocity coordinate system. Experimental studies of a 7.62 mm rifle bullet and a 5.8 mm rifle bullet were carried out through the reflective mirror system. Translational displacements, vertical displacements, lateral displacements, pitch angles and yaw angles of the two bullets were obtained using the linear transformation method. Analysis shows:the translational motions and the rotational motions of penetrating bullets are both spatial motions; the ballistic model can simulate motions of the tested bullet well; the energy dissipation of the bullet increases with the mass and the equatorial inertia; the polar inertia has little effect on the energy dissipation process.