NCJ Number
142983
Journal
Journal of Forensic Sciences Volume: 38 Issue: 3 Dated: (May 1993) Pages: 585-592
Date Published
1993
Length
8 pages
Annotation
In studying the accuracy of range-of-fire estimates in shotgun pellet patterns at fixed intervals, this study also examined the effect of barrel and shell temperature changes on the diameter of pellet patterns.
Abstract
One hundred firings were made using a Remington model 870, 12-gauge pump action shotgun; ammunition used was commercially available 12-gauge Winchester-Western, 00 buck, shot shells. In 20 shots, the shotgun barrel temperature had been lowered; in 20 shots, the shell temperature had been lowered; and in 60 shots, the barrel and shell temperatures were maintained at ambient values. The results showed that temperature effects may have an undesirable impact on estimation of range-of-fire of shotgun pellet patterns. Specifically, shells that have been exposed to colder temperatures may produce pellet patterns on a much more restricted range than those stored under normal conditions. The reduced temperature produces a slower gun powder burn time, reduces the pressure in the barrel chamber, and lowers the velocity of the shot. As a result, there is less natural deformation of the pellet, less air resistance, and smaller dispersion of the pellets. Therefore, estimation of range-of- fire must be made with knowledge of relevant conditions under which shotgun pellets were stored. 4 tables, 2 figures, and 6 references