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In recent years, sawn-off shotguns have been regularly encountered in firearm-related incidents. Shotgun represents a community threat due to their ability to be shortened in order to improve their concealability. In practice, forensic scientists and investigators may be asked to determine if a shotgun used in a particular event might have been shortened based on the pellet distribution. To investigate the effect of altering the barrel length on pellet distribution, five 12-gauge shotguns were progressively shortened. Each shotgun was assessed at six barrel lengths and a single discharge of No. 4 shot shotshell ammunition was fired at a fixed fabric target. The shotguns were positioned at six different distances from target and experiments conducted in triplicate. The fabric targets containing pellet pattern underwent data analysis to calculate the pellet distribution area. At short distances from target (≤ 1.0 m), the pellet penetration was observed as a single entry point as the pellets did not have a sufficient flight time to spread from each other. For distances of 2.5 m, 5 m and 10 m, pellet penetration patterns were observed and a quantitative analysis was performed on the samples containing pellet distribution patterns. At each of these distances, it was detected that there was a noticeable increase in pellet distribution area between the unaltered shotgun and altered barrel lengths for all shotguns. The distance from the target as well as the presence of a choke in the shotgun's barrel was found to have a greater impact on the pellet distribution than the barrel length.

Pressure sensitive tapes such as duct tape are a common trace type sent for forensic analysis. The limited variation of tape backings and adhesives can provide valuable linkage evidence between a scene, a victim or a person of interest. Fingermarks are also often found on tapes and prioritised over tape analyses. This project aimed to investigate the effects of fingermark enhancement chemicals, namely Wet Powder™, cyanoacrylate and cyanoacrylate stained with rhodamine 6G, on various tapes and their comparison with untreated tapes. The changes in physical and optical features were observed using a Video Spectral Comparator (VSC) and microscopy. Chemical changes were analysed by Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR). Most physical and optical properties were not heavily affected by the treatments. An increase in fluorescence was observed with specimens stained with rhodamine 6G as might be expected. Significant chemical changes were observed in the FTIR spectra produced from cyanoacrylate fuming. Polyethylene backings and rubber adhesives were heavily affected while polypropylene backings were moderately affected. Cellulose backings, polyester and polyacrylate adhesives were not significantly affected. Wet Powder™ treatment proved useful for enhancing fingermarks on most adhesives while leaving behind little chemical residue that might interfere in a forensic comparison.