AFTE Store - Observations on Fluted, Annular-Ringed and Perforated Chambers

Fluted, annular-ringed and perforated chambers produce unique markings on cartridge cases fired in them. Such chambers are found in a limited number of autoloading and automatic arms. This is a useful means of rapid identification of a suspect firearm. Flute markings are viable evidence in determining both class and individual firearm characteristics. Positive comparisons can be obtained solely on the basis of these markings. Different case materials and coatings greatly affect these markings. Weathering, cleaning and handling can obliterate these markings. Under some circumstances, however, these chamber markings persist through several years of weathering or the process of multiple reloadings and firings in an unfluted chamber.