Forensic Ballistics: Comparison Microscopy and Striation Matching

UGC-NET Forensic Science Unit V advanced drill on firearm identification through comparison microscopy and striation matching. Hard-band coverage of striation theory (formation by barrel asperities transferred to bullet bearing surface), the class versus sub-class versus individual characteristics hierarchy, comparison-microscope optical bridge designs (Bausch and Lomb, Leica FS C, Nikon Eclipse), the 4x / 10x / 40x parfocal workflow, and the Consecutive Matching Striae (CMS) framework set out by Biasotti and Murdock in AFTE Journal in 1972, 1984 and 1997. Trial-relevant treatment of the AFTE Theory of Identification with its sufficient-agreement standard and its Range of Conclusions (Identification, Inconclusive A, B and C, Elimination, Unsuitable for examination), the PCAST 2016 critique of the foundational validity of firearm-toolmark examination, and the NRC 2009 Path Forward report. Coverage of sub-class confusion mitigation through consecutively manufactured barrel datasets, and the emerging role of 3D surface-metrology systems (NIST bullet signatures via Vorburger and colleagues, Cadre TopMatch-3D, Topomatix) in moving the discipline toward objective comparison.

Calibrated for MSc Forensic Science and BSc Forensic Science finalists targeting top-decile Paper II scores in firearm-toolmark questions, for NFSU MSc entrance aspirants, and for FACT-track candidates working toward central forensic-science laboratory posts in ballistics divisions.

Topics covered:

• Striation formation theory and Locard transfer to bullet bearing surface
• Class, sub-class and individual characteristics in barrel signatures
• Button-rifled, broached and hammer-forged barrel sub-class sources
• Comparison microscope optical bridge and parfocal objective workflow
• Consecutive Matching Striae and the Biasotti-Murdock threshold
• AFTE Theory of Identification and Range of Conclusions
• PCAST 2016 critique and NRC 2009 path-forward findings
• 3D surface metrology and objective bullet-signature comparison

Sit this paper after revising the comparison-microscope chapter in Heard and the firearm-identification chapter in Saferstein.

Allow 30 minutes.