AFTE Store - Reduction of Characteristic Breechface Marks Due to Primer Sealants

Some brands of ammunition, such as Sellier & Bellot, have a primer sealant applied across the entire surface of the primer. The sealant most often used is a nitrocellulose-based lacquer. Lacquers exhibit plastic properties, allowing them to act as a protective layer between the breech and the base of the cartridge. In this study it was determined that the presence of such sealants reduced the transfer of characteristic breechface marks to cartridge cases. Comparisons with cases that had the lacquer removed prior to discharge characteristically differed in appearance from those fired with the lacquer present. While the grossest class and individual characteristics transferred in both cases, the finest of these marks were consistently lost and the remaining marks were reduced in intensity. Both cartridge cases fired with and those fired without sealant could still be identified as being from the same gun by microscopic examination; however, the differences in the appearance of the striations affected the match quality obtained through the IBIS computerized image matching database.