In order to realize rapid detection for the shootings effectively, a cartridge case compared system of the 3Dtopography is established. We compared the indentation of the firing pin which remained on the cartridge cases todetermine whether the cartridge cases fired from the same gun. First, according to the prior knowledge that tail of cartridge case is circle, we calculated the center of mass which is the indentation of firing pin, rotated a cartridge case around the center of circle, and made the connections of center of mass of two firing pins to center of circle parallel. Then, the cross-correlation measure was calculated based on voxel. In order to improve the matching accuracy, iterative algorithm on adaptive variable coefficients was proposed for calculation of cross-correlation. Experimental results indicate that when the two cartridges are fired from the same gun, the maximum of cross-correlation measure is improved more than 30%, and the average is more than 12%. The result of comparison is stable and reliable; which can satisfy the requirement of the bullets comparison system.