- 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
General Rifling Characteristics
Home > Characterization and Evaluation of Fired Projectiles > General Riflling Characteristics
Broach cut 6-left rifling pattern
Gross impressions visible to the naked eye are made in the surface of bullets while in hard contact with the bore of the barrel. The clockwise or counterclockwise grooves inside a barrel result in groove impressions (higher areas) on the surface of a fired bullet. The areas between the grooves inside a barrel (lands) result in land impressions (lower areas) on the surface of a fired bullet. These gross impressions can be associated with a number of brands and models of firearms of certain classes. In the field of firearms identification, these class characteristics are called general rifling characteristics (GRC).
Although GRCs cannot identify a specific firearm, they are a useful investigative tool. They can provide invaluable lead information to investigators concerning the type of firearm.
