AFTE Store - Propellant Matching in GSR Production and Pattern Deposition

Agreement in propellant type and amount between evidence ammunition involved in a shooting incident and that used for subsequent laboratory powder patterning for a distance determination is critical. Commercial ammunition manufacturers in the United States may, and often do change the propellant source used in a particular product. For a particular bullet and cartridge, the industry’s primary interests are muzzle velocity and peak pressure as measured in a test device. Several
propellants, often with different physical forms, dimensions and amounts may satisfy their performance requirements. Cost and availability of a suitable propellant over months and even years of the production of the product often result in different lots of the same product containing different propellants. Such a difference in propellant can have a pronounced effect on close distance, gunshot residue (GSR) patterns and nitrite responses. Such differences, in turn, may result in a serious error in certain distance determinations via GSR deposition when a different propellant charge is used for the preparation of GSR patterns.

Full Journal: AFTE Journal Vol 56 No 1 (2024)