ON DEFORMATION OF TWO KINDS OF PISTOL BULLETS DURING PENETRATING INTO C30 CONCRETE

The bullet deformation can truly reflect the speed and angle of bullet penetrating into the concrete, which are often used as an important basis for the reconstruction of trajectory and the judgment of shooting position in the process of case detection. Two types of pistol bullets which are 9mm Barabrum bullet and 51type 7.62mm bullet penetrating into C30 concrete at different speeds were test. The results show that the deformed bullet diameter increases with the increase in impact velocity, and the deformed bullet length decreases with the impact velocity. The relation model of bullet deformation characteristics and penetration velocity is established. The function Y is established to analyze the deformation characteristics of bullet. The relationship between Y value and impact velocity can be regarded as a piecewide linear function. The piecewide speed is consistent with the critical speed of bullet jacket cracking and breaking. The critical speed of bullet jacket cracking and breaking is about 130 m/s for 9 mm bullet and 230 m/s for 51 type 7.62 mm bullet. Function Y can well reflect the deformation law of bullet penetrating into C30 concrete at different speeds.