Análise de balística terminal em pele suína: experimentação com pistolas 9mm

Abstract

Firearms are responsible for approximately 70% of intentional violent deaths in Brazil, making forensic ballistics essential for criminal investigations. Terminal ballistics, which studies the injuries produced and the associated residues, has shooting distance estimation as a key aspect. For this purpose, it is necessary to develop methodologies that relate the generated residues to shooting distances. Experimental simulation emerges as an alternative, with cardstock and pigskin as viable analytical supports. Studies on distance estimation for 9x19 mm pistols are scarce, as indicated by the bibliometric analysis conducted. This study compared the characteristics of perforations and residues generated by Beretta APX Full Size and Sig Sauer P320 pistols, using 124-grain ogival EOOG NTA (Non-Toxic Ammunition) projectiles. Tests were conducted in both indoor and outdoor environments, varying the distance between the shooter and the target from 0 to 150 cm, with triplicate experiments for each condition. Based on the experimental data, a mapping of injuries and scanning electron microscopy findings was developed. Images from the experiments were analyzed using the ImageJ software for automatic lesion area measurement. The results indicated that cardstock is more suitable for gunshot residue analysis, while pigskin is more effective for lesion observation and electron microscopy. Residues on the cardstock were more evident up to 30 cm, progressively decreasing until they were nearly absent at the farthest distance. The variation between manufacturers and environments was minimal, with distance being the primary influencing factor. In pigskin, residue patterns did not follow a uniform trend, possibly due to material variability. The Beretta pistol demonstrated greater consistency in lesion size and residue quantity across both supports and environments. Scanning electron microscopy did not identify typical firearm residues due to the use of NTA ammunition but revealed compounds related to gunpowder, metals, contaminants, and the primer. Since the analysis was not quantitative, it was not possible to correlate the observed geometry with specific chemical elements. These findings contribute to improving forensic methodologies for gunshot distance estimation and ballistic residue characterization