Ohio BCI Laboratory LM-Firearms Methods Issuing Authority: Laboratory Director Effective Date 08/28/2020 Revision 18 Page 1 of 54 Firearms Methods Manual Table of Contents 1 Procedure for the Examination of Firearms ............................................................... 4 1.1 Safety Considerations ......................................................................................... 4 1.2 Safe Firearm Handling......................................................................................... 4 1.2.1 Pre-firing safety examinations........................................................................ 5 1.2.2 Test Firing and Evidence Examination ............................................................ 5 1.3 Examination Documentation.............................................................................. 6 1.4 Physical Examinations......................................................................................... 7 1.4.1 Foreign Material.............................................................................................. 7 1.4.2 Barrel & Overall Length Measurement........................................................... 7 1.4.3 Rusted Firearms ............................................................................................ 10 1.4.4 Firearm Malfunction Examination................................................................ 10 1.4.5 Bore/Chamber Casting.................................................................................. 12 1.5 References ........................................................................................................ 13 2 Procedure for Test Firing .......................................................................................... 15 2.1 Introduction ...................................................................................................... 15 2.2 Safety Considerations ....................................................................................... 15 2.3 Procedure.......................................................................................................... 15 2.4 Remote Firing.................................................................................................... 16 2.4.1 Technique...................................................................................................... 16 2.5 Downloading..................................................................................................... 16 2.5.1 Technique...................................................................................................... 16 2.6 Primed Cartridge Case/Shotshell/Percussion Cap/ Primer .............................. 17 2.6.1 Technique...................................................................................................... 17 2.7 Interpretation of Results................................................................................... 17 2.8 References ........................................................................................................ 17 3 Procedure for Fired Evidence Examination .............................................................. 18 3.1 Safety Considerations ....................................................................................... 18 3.2 Preparations...................................................................................................... 18 3.3 Physical Examination and Classification of Fired Bullets, Cartridge Cases and Shotshells ...................................................................................................................... 19 3.4 Foreign Material................................................................................................ 19 3.5 Caliber Determination ...................................................................................... 19 3.5.1 Interpretation of Results............................................................................... 20 3.6 Land and Groove Width Impression Measurement ......................................... 20 3.6.1 Micrometer Method ..................................................................................... 21 3.6.2 Interpretation of Results............................................................................... 21 3.7 General Rifling Characteristics Utilization ........................................................ 21 3.8 Shotshell Wadding Examination....................................................................... 21 3.8.1 Interpretation of Results............................................................................... 22 3.9 Shot Pellet Examination.................................................................................... 22 This document is uncontrolled if viewed outside the BCI document management system. Ohio BCI Laboratory LM-Firearms Methods Issuing Authority: Laboratory Director Effective Date 08/28/2020 Revision 18 Page 2 of 54 3.10 Microscopic Comparison .................................................................................. 22 3.10.1 Interpretation of Results........................................................................... 23 3.11 References......................................................................................................... 25 4 Procedure for Tool Mark Examination...................................................................... 26 4.1 Safety Considerations ....................................................................................... 26 4.2 Initial Physical Examination .............................................................................. 26 4.2.1 Interpretation of Results............................................................................... 27 4.3 Foreign Material................................................................................................ 27 4.4 Tool Mark Comparison...................................................................................... 28 4.4.1 Test Standards .............................................................................................. 28 4.4.2 Casting........................................................................................................... 28 4.5 Microscopic Comparison .................................................................................. 28 4.5.1 Interpretation of Results............................................................................... 29 5. References ................................................................................................................ 29 5 Procedure for Serial Number Restoration................................................................ 31 5.1 Introduction ...................................................................................................... 31 5.2 Safety Considerations ....................................................................................... 31 5.3 Preparations...................................................................................................... 32 5.4 Polishing............................................................................................................ 33 5.4.1 Technique...................................................................................................... 33 5.5 Chemical Restoration........................................................................................ 34 5.5.1 Reagent reliability testing............................................................................. 34 5.5.2 Technique...................................................................................................... 34 5.6 References ........................................................................................................ 34 6 Acquisition Protocols for NIBIN ................................................................................ 35 6.1 Types of Specimens........................................................................................... 35 6.2 Case Maintenance Fields .................................................................................. 35 6.3 Correlation Analysis .......................................................................................... 35 6.4 Confirmation..................................................................................................... 35 7 Standards and Controls............................................................................................. 36 7.1 Verification........................................................................................................ 36 7.1.1 Disputed Verifications................................................................................... 36 7.2 Test-to-Test Comparisons................................................................................. 36 7.3 Prepared Reagents............................................................................................ 36 7.3.1 Container Labeling ........................................................................................ 36 7.3.2 Documentation ............................................................................................. 36 7.3.3 Quality Control Tests .................................................................................... 36 8 Equipment Calibration and Maintenance................................................................. 38 8.1 Introduction ...................................................................................................... 38 8.2 Microscopes.....................................................................................................