The Firearms and Toolmarks Section is responsible for the comparison of firearms, cartridge cases, fired shotshells, projectiles, and other evidence that may be associated through toolmarks. Toolmarks result whenever two items come into contact with one another with sufficient force such that one or both of the items bear markings resulting from the other item.
The most important method utilized in the Firearms and Toolmarks Section is comparison microscopy which allows two items to be viewed simultaneously. Evidence projectiles, cartridge cases, or other items bearing toolmarks are compared to known items in order to determine consistency or inconsistency in both class characteristics and individual characteristics. Other examinations performed by the Firearms and Toolmarks Section include functional testing of firearms, distance determinations, and serial number restorations.
The Crime Laboratory offers firearms testing in Austin, El Paso, Garland, Houston, Lubbock, Weslaco and Tyler. Please see the Laboratory Customer Handbook (excerpt from Crime Laboratory Service Manual) (PDF) for details.