The Long Range Deposition of Gunshot Residue and the Mechanism of Its Transportation

A review of the literature concerning the fate and behavior of gunshot residue (GSR) is presented. A number of concomitant parameters including firearm and ammunition type, plume and GSR material characteristics, travel distances, chemical composition and GSR morphology are critically discussed in relation to their effects on the distribution and deposition, transfer and persistence processes of GSR. The underlying mechanisms associated with such processes are also considered. Knowledge of these processes on GSR materials could provide valuable information concerning scene preservation and subsequent forensic sampling. The number of GSR particles deposited can vary significantly with each firearm discharge, highlighting the potential to produce distinctive data in each individual case. With the continual development and compositional changes of new ammunition types, further evaluation of the effect these processes may have on GSR evidence and their possible influence on the interpretation of the analytical results should be given due consideration.

Section: Distribution Of Gsrsupporting

confidence: 92%

“…GSR has been identified at distances as far as 18 meters (m) from the shooter (see Table ). As you move away from the shooter, GSR deposition and distribution changes.…”

Section: Distribution Of Gsrmentioning

confidence: 99%

Fate and Behavior of Gunshot Residue—A Review

Blakey

Sharples

Chana

et al. 2017

“…Deposition of GSR is, in general, a fairly random process that can be affected by any number of incidental factors (e.g., air currents, barrel length, action design). GSR deposition has been well studied based on both weapon type and sampling position relative to discharge exposure, including how the quantity and distribution of GSR recovered can vary widely from one firing to another using the same firearm . No distinct correlation was observed between either the quantity or size of GSR captured and the relative position of the stub.…”

Section: Resultsmentioning

confidence: 99%

Preparation of a Ytterbium‐tagged Gunshot Residue Standard for Quality Control in the Forensic Analysis of GSR

Hearns

Laflèche

Sandercock

2015

Preparation of a ytterbium-tagged gunshot residue (GSR) reference standard for scanning electron microscopy and energy dispersive X-ray spectroscopic (SEM-EDS) microanalysis is reported. Two different chemical markers, ytterbium and neodymium, were evaluated by spiking the primers of 38 Special ammunition cartridges (no propellant, no projectile) and discharging them onto 12.7 mm diameter aluminum SEM pin stubs. Following SEM-EDS microanalysis, the majority of tri-component particles containing lead, barium, and antimony (PbBaSb) were successfully tagged with the chemical marker. Results demonstrate a primer spiked with 0.75% weight percent of ytterbium nitrate affords PbBaSb particles characteristic of GSR with a ytterbium inclusion efficiency of between 77% and 100%. Reproducibility of the method was verified, and durability of the ytterbium-tagged tri-component particles under repeated SEM-EDS analysis was also tested. The ytterbium-tagged PbBaSb particles impart synthetic traceability to a GSR reference standard and are suitable for analysis alongside case work samples, as a positive control for quality assurance purposes.

“…GSR in this second class either adheres to the bullet due to the high heat of the bullet itself or travels in the low pressure vortex in the wake of the bullet . It has been demonstrated that GSR particles are shed along the path of the bullet for as far as 60 feet . GSR particles can also be found around the entrance hole and on the back of the bullet on target distances over 650 feet (200 m) downrange .…”

mentioning

confidence: 99%

“…It has been demonstrated that GSR particles are shed along the path of the bullet for as far as 60 feet . GSR particles can also be found around the entrance hole and on the back of the bullet on target distances over 650 feet (200 m) downrange .…”

mentioning

confidence: 99%

Transfer and Distribution of Gunshot Residue through Glass Windows

Greely

Weber

2017

Research into the deposition patterns of primer gunshot residue (GSR) beyond a primary target was previously nonexistent. This study aimed to determine the deposition patterns of GSR once a bullet passed through an initial target and continued on its path into additional targets. Multiple repetitions were performed to assess the GSR deposition patterns after a bullet was shot through a closed window into either a dummy or a wall within an enclosed room. Samples were taken from both the primary and secondary target holes as well as from nontarget areas. Significant amounts of GSR were found on all samples. The results show that GSR continues to be deposited along the path of the bullet after passing through a primary glass target. These findings reiterate the lack of probative value in collecting GSR samples from gunshot victims even if they are in an enclosed area separate from the shooter.