AFTE Store - Equivalent Circle Circumference Method for Shotgun Distance Determination

The equivalent circle circumference method is a way to quantitatively describe a shot pattern. This method was used to establish and demonstrate the linear relationships between muzzle-to-target distance and the circumference of the shot patterns of three different shotgun loads fired from the same shotgun. The method provides an additional tool for examiners doing distance determination using shotguns. Additionally, a prediction interval was determined to provide a range to the theoretical distances calculated using the equivalent circle circumference method that is consistent with traditional approaches to shotgun distance determination casework.