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2019-01 Colorado Mesa University

Most archeologists and curators can only identify a bullet or cartridge case to caliber. This project is an innovative use of microscopically accurate forensic casting technology and testing of digital imaging technology that resulted in a database of rifling characteristics for 788 firearms that can be used to identify some common pre-1900 rifled firearm ammunition components to type, model, or gunmaker. The database includes for each gun listed: land and groove measurements, number of land and grooves, and twist or rifling direction.  The database is designed to allow users to identify or at least narrow possible identifications to gun

Man using an instrument on a firearm

Using a bore light to determine the condition of the rifling on a Gatling gun at the National Firearms Museum.

types based on land and groove measurements found on bullets. The information will allow researchers and interpreters to determine with greater accuracy the type of guns used at sites where ammunition components are found, potentially leading to greater accuracy in the interpretation of firearms use, troop deployment, and possibly small unit actions on battlefields. It will also allow a greater understanding of the actual arms used at sites and in battles employing physical evidence as a primary identification method.

The project employed a 3D scanner to make accurate scans of the land and groove casts. The original intent was to link scans to the database, but the 3D scans were found to lack sufficient detail for comparative value. Standard digital photography and panoramic photography were tested for comparison purposes.

Instrument emitting laser beams to scan rifling cast

NextEngine scanner during the process of scanning a rifling cast.

Additional information was collected and is presented on firing pin shapes for pre-1900 firearms that fired metallic self-contained cartridges. Firing pin shape varied significantly until the late nineteenth century. Presentation of the firing pin shape information will aid archaeologists and curators in identifying gun types represented by fired cartridges recovered in archeological contexts.

Rifling characteristics of pre-1900 rifled artillery were opportunistically recorded during the project. Rifling data on several Civil War, American Indian War, and Spanish American War rifled artillery are presented as well. These data may aid in identifying cannon type when fired projectile driving bands or sabots are recovered archeologically.