Empirical evaluation of spring powered air rifle storage and modifications on forensic practice and casework

Abstract

Air weapons are commonly used by civilian populations across the world, particularly by those under 18, and discharges often result in desecration, criminal damage and animal abuse. Online forums and websites provide an accessible resource for civilians to access airgun modification methods proposing to increase muzzle velocity. However, there is limited published research that empirically evaluates the impact of air weapon modification and the potential to influence casework interpretation. Therefore, this paper aims to initiate such research by quantifying the effect of storage conditions (mainspring compression and oil travel/dieseling) and two modifications (reduction of barrel length and preloading through addition of washers) encountered in casework on recorded muzzle velocities using a small number of break barrel, spring powered air rifles.

Interpol review of forensic firearm examination 2019–2022

“…By using a small number of break barrel, spring powered air rifles for their study, they found a significant variation in muzzle velocities as a result of the two earlier mentioned modifications. They also found that the orientation of storing (vertically) and/or cocking statistically effected the consistency of recorded muzzle velocities, reinforcing the requirement to undertake the weapon examination in short order [ 100 ].…”