A note on assessability of firing distance from gunshot residues

Abstract

The quantitatively measurable evidence on a target (e.g. cloth, skin, etc.) due to bullet impact is the gunshot residue (GSR) deposited around the bullet hole and it is the only material available for extracting any quantitative information about the gun discharge from an examination of the target. At close ranges, the gaseous cloud of GSR particles is directly transported onto the target producing a radial distribution of GSR upto a few centimetres around the bullet hole. Some GSR particles are also captured on the bullet surface and transferred to the target through bullet contact during its penetration. Such bullet-carried GSR is deposited on the target at all ranges, but just around the hole margin. GSR deposits on targets resulting from the above two transfer modes can be distinguished and both processes have been investigated to evaluate the infuence of firing distance on the respective GSR deposits on targets. Two different methodologies have been proposed for close and long range estimations with the aid of GSR measurement. The proposed models are found to give encouraging results when tested against available experimental data.