When a bullet is propelled from the barrel of a firearm, many different compounds, including partially burnt and unburnt propellant particles, known as gunshot residues are also expelled from the muzzle in a cone shape, similar to pellets expelled from a shotgun. Depending on the muzzle to target distance, these residues may be deposited on the surface of the target. The examiner can visualize the residues on a target surface using various color test methods. Then, using the same firearm and ammunition that produced the evidence pattern, the examiner creates multiple test patterns for comparison to the evidence patterns. The examiner is thus able to estimate the distance between the muzzle of the firearm and the target, based on agreement of characteristics between evidence patterns, and known test patterns produced in the laboratory.
