構造物に衝突した硬鉛弾の形状と衝突角度の関係

抄録

 In a case that a gun shooting crime occurs, investigators are required to estimate the shot position, shot direction and the types of gun used at the scene. The lead bullets with revolvers calibered as 38SPL are used more often than metal-jacketed bullets at shooting crime scenes in Japan. The fired bullets picked up at the scenes are deformed in many cases, and sometimes fragmented, because of the collision against a structure.
 There is almost no report focused on the relationship between the angle of collision and the feature of lead bullet fragments. This paper gives the relationship based on the experimental result that the lead bullet collided against the steel plate or concrete block as rigid bodies.
 As a result, the heel of a lead bullet was fragmented by the collision against rigid body in the case that the angle of collision was more than 60°, and not fragmented in the case that the angle of collision was less than 30°.