MacCrehan William A, Reardon Michelle R, Duewer David L
Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, MD 20899-8394, USA.
J Forensic Sci. 2002 Mar;47(2):260-6.
Qualitatively identifying and quantitatively determining the additives in smokeless gunpowder to calculate a numerical propellant to stabilizer (P/S) ratio is a new approach to associate handgun-fired organic gunshot residues (OGSR) with unfired powder. In past work, the P/S values of handgun OGSR and cartridges loaded with known gunpowders were evaluated. In this study, gunpowder and residue samples were obtained from seven boxes of commercial 38 caliber ammunition with the goals of associating cartridges within a box and matching residues to unfired powders, based on the P/S value and the qualitative identity of the additives. Gunpowder samples from four of the seven boxes of ammunition could be easily differentiated. When visual comparisons of the cartridge powders were considered in addition to composition, powder samples from all seven boxes of ammunition could be reliably differentiated. Handgun OGSR was also collected and evaluated in bulk as well as for individual particles. In some cases, residues could be reliably differentiated based on P/S and additive identity. It was instructive to evaluate the composition of individual unfired gunpowder and OGSR particles. We determined that both the numerical centroid and dispersity of the P/S measurements provide information for associations and exclusions. Associating measurements from residue particles with those of residue samples collected from a test firing of the same weapon and ammunition appears to be a useful approach to account for any changes in composition that occur during the firing process.
定性识别和定量测定无烟火药中的添加剂，以计算推进剂与安定剂的数值比（P/S），是一种将手枪发射的有机枪弹残留物（OGSR）与未发射火药关联起来的新方法。在过去的工作中，对手枪OGSR和装有已知火药的弹药筒的P/S值进行了评估。在本研究中，从七盒商业38口径弹药中获取了火药和残留物样本，目的是根据P/S值和添加剂的定性特征，将一盒内的弹药筒关联起来，并将残留物与未发射的火药进行匹配。七盒弹药中有四盒的火药样本可以很容易地区分。除了成分外，当考虑弹药筒火药的视觉比较时，所有七盒弹药的火药样本都可以可靠地区分。还对手枪OGSR进行了批量和单个颗粒的收集与评估。在某些情况下，可以根据P/S和添加剂特征可靠地区分残留物。评估单个未发射火药和OGSR颗粒的成分很有启发性。我们确定，P/S测量的数值质心和离散度都为关联和排除提供了信息。将残留物颗粒的测量结果与从同一武器和弹药的试射中收集的残留物样本的测量结果关联起来，似乎是一种有用的方法，可以解释射击过程中发生的任何成分变化。
