Modern centre fire ammunition from Western countries, that is, Europe, America, Sweden, Australia and New Zealand, and so on, all contain a very similar priming composition, the basic elements found being Pb, Ba and Sb with calcium silicide and/or powdered glass giving silicon (Si). With so little variation, it is therefore very difficult to make any differentiation between calibres and origin.
Aluminium (Al), or sometimes magnesium (Mg), is also often added to increase the temperature and burn time of the flame produced. This is usually found in the higher-pressure cartridges, that is, 9 mm PB, 0.357" Magnum and +P cartridges. This can sometimes be useful in identifying the type of ammunition fired.
A case illustrating this involved a very large and determined gang of heavily armed robbers who, after robbing a bank of several tens of millions of dollars, became involved in a running shoot-out through the streets. At one point, an innocent bystander turned a corner and was shot in the head by one of the culprits. The bullet was a 0.357" Magnum, and GSR found on the base of the bullet contained Pb, Ba, Sb, Si and Al. This was the only round of 0.357" Magnum fired during the chase, the rest being 0.38" Special, none of which contained Al in the GSR.
Sometime later, a number of string gloves were found on a hillside along with some of the stolen money and guns. It was easy to determine from GSR found in the cloth material of the gloves which was used to fire the 0.357" Magnum round and it was easy to determine which of the guns had fired the fatal bullet. Luckily, the glove which had the GSR containing the Al on it also had some blood from where the wearer had cut his hand on some glass. Eventually, the suspects were located, and it was just a matter of blood grouping them to determine who had been wearing the glove which was used to fire the fatal shot.
Centre fire ammunition from what was previously called the Warsaw Pact countries, that is, Russia, Poland, Czechoslovakia, Hungary, Romania, as well as China and Korea tend to have a completely different primer composition. Generally speaking, the priming compounds are much more corrosive than those found elsewhere in the world.
The basic elements found in these priming compounds are:
Other compounds occasionally encountered include:
• lanthanum/cerium/iron (basically lighter flint).
It is this great diversity of elements which, in some circumstances, enables the identification of calibre, country of origin and sometimes even a factory code from the GSR composition.
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