Every firearm possesses minute imperfections caused by the manufacturing process as well as the use, abuse, erosion, and corrosion of the firearm. During discharge of ammunition, these imperfections leave markings on the ammunition components, principally the bullet and the cartridge case base. The Integrated Ballistics Identification System (IBIS) is an automated instrument that correlates fired bullets and cartridge cases and searches through thousands of entries in a database to generate a list of possible matches. There is question raised as to whether an automated system like the IBIS would be susceptible to the minute changes incurred with increased firearm use and would then assign lower scores. This study sought to determine whether the brand of ammunition, firearms use, and other factors used to test-fire firearms affected IBIS scores. Twenty-five rounds of Federal, Remington, and Winchester jacketed ammunition were fired through 3 semi-automatic pistols. The results showed that no single brand performed best in all calibers or all types of markings studied. Only the .38 caliber bullets consistently showed the expected inverse relationship between IBIS scores and the number of rounds fired between correlated samples. In light of the results, it does not appear as though entering any of the 25 test-fires following confiscation of a firearm would significantly and negatively affect the IBIS score generated. Figures and references