Identification of polygonal barrel rifling characteristics in bullet wipe residue deposited on textiles.

This study examines the potential formation of land and groove rifling characteristics in bullet wipe residue deposited on textile fabrics. Textile fabrics comprised of natural, synthetic, semi-synthetic, and blended fibers were damaged either individually or as triplicate layers using two different ammunition types: Winchester WinClean 115 grain 9 mm Luger BEB and Speer 115 grain 9 mm Luger TMJ. Each ammunition type was fired in triplicate using a 9 mm Luger caliber Glock 17 at a distance of approximately 6 feet at normal incidence to the target. The bullet hole was first observed under a stereomicroscope, photographed under tungsten and infrared illumination to observe chemical residues, and subsequently tested for the presence of copper and lead residues. The preliminary chemical results show that land and groove rifling class characteristics can form in bullet wipe residue deposited on textile fabrics. The composition of the fabric, cleanliness of the interior surface of the firearm barrel, presence of intervening layers of fabric, and the bullet type are all potential contributing factors to the detection of rifling characteristics.