Course LogoFirearm Examiner Training
Print Page Previous PageNext Page

FBI GRC File Standards

Home > Characterization and Evaluation of Fired Projectiles > General Riflling Characteristics > FBI GRC File Standards

The FBI GRC file is a collection of well-documented, known GRC data that can be used as a standard for comparison of class characteristics of no-gun submission evidence bullets. The GRC digital database file can be searched electronically or in print form.

The general rifling characteristics derived from a fired evidence bullet are an indication of the brand(s) and model(s) of firearm from which the bullet could have been fired.

GRC file page

Courtesy of Ronnie Freels

The data obtained from a fired bullet provides the input data for searching the GRC file, including

  • caliber,
  • number of lands and grooves,
  • direction of twist,
  • land and groove impression measurements,
  • other information.

The examiner must use experience, skill, and judgment to determine and refine the parameters of the search criteria entered into the GRC file. The GRC search produces a list of potential firearms from which the bullet could have been fired.

< Previous Page  ::  Next Page >

Association of Firearm and Tool Mark Examiners logo
Submit Change Request