10.3 Matching Crime and Testing Bullets and Cartridge Cases in Firearms

The comparison's process: the test firing (the suspect gun's evidence-bullets-and-cases produced under the lab's controls); the comparison-microscope (the side-by-side — the bullets'- and-cases' microscopic striae); the matching (the lands-and-grooves's agreement — the consecutive-matching-striae criteria); the cartridge case's marks (the firing pin's impression, the breech face's marks, the extractor-ejector's traces — the gun's signature on the case). The evidence's collection: the bullets-and-cases at the scene (the location's documentation — the trajectory's input); the wounding's recovery (the autopsy's-and-surgery's bullets). The conclusions' discipline: the identification-to-the-firearm (the match's strength); the elimination; the insufficient-marks' honesty.