- 01: Introduction
- 02: History
- 03: Propellants, Firearms, and Ammunition Development
- 04: Modern Firearms Manufacture
- 05: Small Arms Ammunition
- 06: Evidence Handling Procedures
- 07: Equipment and Instrumentation
- 08: Examination of Firearms
- 09: Cartridge and Shotshell Examination
- 10: Characterization and Evaluation of Fired Projectiles
- 11: Bullet Comparison and Identification
- 12: Gunshot Residue and Distance Determination
- 13: Toolmark Identification
- 14: Communicating Results
- Resources
Measuring Impressions
Home > Characterization and Evaluation of Fired Projectiles > General Riflling Characteristics > Measuring Impressions
Most general rifling characteristics can be readily observed using the naked eye. However, the determination of the dimensions (width) of land and groove impressions presents additional considerations.
These considerations include the following:
- The widths of the land and groove impressions are small and must be accurately measured.
- A discipline-wide technique must be used to ensure reproducibility of results to compare against a standard.
For measurement accuracy and reproducibility, reference points that are common to all bullets fired from conventionally rifled barrels must be established. These reference points define the location at which a land impression meets a groove impression. The width of the land impression is the width of the floor; the plateau and both adjacent slopes define the width of the groove impression.
