2013
Frederick Schmidt
Albuquerque, NM
The observation of "witness marks" on firearms and ammunition is often observed visually even with significant magnification with little actual knowledge of the metal structure below. This presentation will show the actual gradients between fully annealed soft metals and the possible changes that result from use and mis-adventures. Case examples will be presented to clearly illustrate the value of knowing how metallurgical analyses can assist toolmark examiners. Steel, the types of steel, copper, brass, and electro deposits were analyzed from a metallurgical perspective to clearly show the cause/effect relationship between observations (toolmarks) and the underlying metallurgical conditions to explain and prove the validity of the conclusions. Metallurgical microstructural understanding can be a considerable aid in supporting and proving toolmark examiners observations.