Distance Determination Essay

The term distance determination corresponds with Forensic Gunshot Residue Distance Determination Testing. Distance determination is the process of determining the distance a firearm was shot from its intended target. The determination process requires the firearm to be test fired from various distances to compare gunshot residue (GSR) patterns made during the test and compared to the ones made on the target. Often times the request for distance determination occurs resulting in the death from a shooting.
When a firearm is fired the firearm ammunitions propellant (gun powder) propels the projectile or projectiles forward down the barrel of the firearm. The expanding gas from the firearm ammunition propellant causes these gases to exit the barrel with the projectile. In all cases there is residue of partially burned and unburned gunpowder expelled after shot. If the firearm is shot close enough to the target the residue of partially burned and unburned gunpowder deposits on to the target in a cone shaped pattern. The size of the cone
shaped pattern of gunpowder particles that are located around the bullet impact can be used to determine the distance between the firearm and target.
Do to variations that occur with each incident, the accuracy of determining the distance can also vary on occasion. An example would be if the investigator was able to seize the firearm used in the incident, this would greatly increase the accuracy of the test. But if no firearm could be located for testing purposes the forensic laboratory has to rely on interval distances from the firearm to target. The accuracy of determining the distance is calculated by a series of rounds being fired and an evaluation of the powder residue that remains on the various targets from different distances.
Two different shooting incidents where distance determination can establish the facts of what occurred are incidents where victims have sustained gunshot wounds and the other are suicides that involve a firearm.
It is critical in an investigation involving gunshot wounds to determine the distance between the weapon that was fired and the victim. Often times these investigations involve one of the parties involved claiming self-defense as their reason for shooting. Thus by analyzing the distance between the suspect’s firearm and the victim, it can either prove or disprove the self-defense claim. The examination of a victim who had committed suicide, often times these wounds are at relatively close range or contact gunshot wounds. In distance determination the absence of certain key pieces of evidence may suggest that a close range wound or contact wound from the firearm may indicate that death was not a result of being
self-inflicted.
In conclusion, the use of distance determination to assist in determining the distance a firearm is a vital tool for law enforcement in many types of criminal investigations. Regardless of the circumstances involving the case the goal is to get the approximately distance from the target the firearm was shot. This will in turn help prove or disprove certain facts of the case.