著者

戸山 恭平 平島 昭雄 竹下 尚紀 西嶋 靖治

出版者

日本法科学技術学会

雑誌

日本法科学技術学会誌 (ISSN:18801323)

巻号頁・発行日

vol.18, no.1, pp.23-33, 2013 (Released:2013-02-20)

参考文献数

15

被引用文献数

1

---

In order to estimate type and trajectory of the fired bullet from the analysis of the ricochet mark, we carried out the gunfire test against the inclined target. 1.2 mm thin steel plates were used as intermediate targets in this study. The following are types of cartridges which were used: 25 AUTO., 32 AUTO., 7.62 mm Tokarev, 380 AUTO., 38 SPL. (FMC), 38 SPL. (LRN), 9 mm Luger and 45 AUTO.. The target was put in a wooden frame. The angle of incidence was changed by rotating the wooden frame.   We could classify the deformation morphology on the thin steel plate into 4 patterns: Ricochet mark without the crack (Type 1), Ricochet mark with the small crack (Type 2), Ricochet mark with the large crack (Type 3), Penetration (Type 4). Metal from the bullet surface was left on the surface of the target. It was thought that the crack in the edge of the ricochet mark (Type 2 or 3) was caused by the friction arising from the rifling rotation of the fired bullet. The length of the ricochet mark in the longitudinal direction L increases with increase of the kinetic energy of the bullet E. The value of L was relative to the kinetic energy resolved into the horizontal component of the velocity Ecos2θi (θi: the angle of incidence). Except for 380 AUTO. and 38 SPL., the value of L was almost independent of E and Ecos2θi respectively. The ratio of the angle of ricochet θr to the angle of incidence θi was around 1 to 2. Therefore, caliber and type of a fired bullet and the trajectory can be determined from the analysis of the ricochet mark and the contour when the bullet is fired into a 1.2 mm thin steel plate.