FM6.1 | Firearms: Types, Ammunition & Terminology — Summary & Reflection

KEY TAKEAWAYS

Firearms are classified by mechanism (single-shot, repeating/semi-automatic, automatic) and by barrel character (smooth-bore vs rifled). Handguns (revolver, pistol), shoulder arms (rifle, shotgun), and country-made weapons are the principal categories encountered in Indian forensic practice. A complete cartridge contains four components: case, primer, propellant, and bullet/projectile. Bullet types — FMJ, hollow-point, soft-point, slug — determine wounding capacity. Black powder (older, heavy sooting) differs from modern smokeless powder (nitrocellulose-based, GSR particles detected by SEM-EDX) in residue pattern and forensic testing. Key terminology: caliber (bore diameter / cartridge designation), muzzle velocity (determinant of tissue destruction), range (distance from muzzle to target — the parameter the forensic physician estimates), trajectory, and choking (muzzle constriction controlling pellet spread in shotguns). Evidence preservation — GSR swabs before washing, proper packaging, documented chain of custody — is as important as wound interpretation for the medico-legal case.

REFLECT

Consider a scenario in which two doctors give differing court testimony about the same gunshot wound: one calls it a 'pistol wound,' the other says 'rifle wound.' Both are confident, but their conclusions differ. Reflect on what specific observations — wound diameter, bullet recovery, rifling marks, muzzle velocity indicators, residue pattern — each doctor should have documented to support or exclude each weapon class. What does this exercise reveal about the relationship between technical knowledge of firearms and the forensic physician's credibility as an expert witness? How would you, as the attending forensic physician, structure your post-mortem report to anticipate and address this kind of cross-examination challenge?