Ricochet of 9-mm luger bullets off plywood, medium-density fiberboard, and melamine board: An empirical investigation in aid of shooting reconstruction.

Ricochet is the glancing rebound of fired bullets from surfaces and is regularly reported during shooting incidents worldwide. Although existing scientific literature presents many ricochet-related empirical works in aid of shooting incident reconstructions, studies focusing on commonly used bullets ricocheting off modern target surfaces found in contemporary urban environments are still limited and continuously in demand. This empirical-based ricochet study presents exciting findings about the ricochet behavior of 9-mm luger bullets with the three most popular engineered wood types present in modern society: plywood, melamine, and medium-density fiberboard (MDF). To evaluate the ricochet behavior and impact evidence, two different mounted firearms, each discharging 9-mm luger bullets, were used to fire at engineered wood targets held at low angles to the impacting bullets. This study reports the first documented observation of a strong statistical relationship between the angles of incidence and ricochet during 9-mm luger bullet ricochet on plywood, melamine, and MDF. Evidence is also provided of a relationship between a bullet's angle of incidence and its corresponding ricochet marks on tested wood targets, not previously highlighted in wood-based bullet ricochet studies, and the critical angles reported for these engineered wood types ranged between 14 and 18 degrees. Additionally, the first observation of "wood spalling" during a ricochet event is presented, offering important insight into the process of bullets ricocheting off layered structures and being of great forensic significance for future scene reconstructions.