Distance determinations are performed in an attempt to approximate muzzle-to-target distance at the time of a suspect firearm being discharged. Distance determinations are possible because, residues, along with the bullet, are discharged from the muzzle at the time a firearm is fired. These residues may leave a pattern on the target that may be analyzed to ascertain the muzzle-to-target distance.
Visual examinations along with microscopic and chemical examinations are conducted on the questioned bullet hole to obtain a pattern for analysis. The suspect firearm and suspect ammunition are test fired into similar target material at varying ranges. These tests are then analyzed in the same way as the questioned bullet hole is. An approximate range can be concluded when the questioned pattern is compared to the test fired targets.