What are tracer rounds and what do they do
The first thing to know about tracer rounds is that they are bullets, just like standard ammunition rounds. What makes tracer rounds different though, is that they eject a small amount of pyrotechnic material (sulfur or magnesium) in order to produce a trail of evidence once fired. Tracer round ammo is typically used for two reasons: to see where it is going, and for marksmanship purposes. Since tracer rounds leave a trail of light that can be seen by the shooter, they also act as a visual marker for other people to understand where impact occurred.
A characteristic of tracers is that they usually remain lit for a short period of time, and then go out. This property makes them ideal for marking targets, as the light trail will stay visible for a few seconds after impact.
How does it work? The pyrotechnic material causes the bullet to leave behind a trail of light when shot. Instead of relying on an explosive charge to cause the bullet to leave a fire trail, sulfur or magnesium are combined with the cartridge to produce a burnable residue. Once fired, the burnable residue burns off and leaves behind a trail of light. [ARTICLE END]
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Title:New York Times: Tracing bullets to help solve crimes [ARTICLE START]
SUNNYVALE, Calif. – Over nearly two decades, the police in this Silicon Valley enclave have gathered the makings of a top-secret gunpowder program.

How can you tell if someone is using tracer rounds
Tracer rounds are made in two different types: single-use and disposable. Single-use tracer rounds are only loaded once, then discarded as soon as they are fired. Disposable tracer rounds remain in the shell after firing and continue to burn on impact. These round types can be identified because reusable tracer rounds have a solid/colored tip, whereas disposable rounds have a hollowed out tip. Some countries, such as the US, only use single-use tracer rounds due to their flammability.
Tracer rounds are used in combat to allow soldiers to identify the location of their enemy. Tracer rounds function as an easy way for soldiers in a trench to see where bullets are coming from so they can return fire on the enemy.
https://www.quora. com/How-can-you-tell-if-someone-is-using-tracer-rounds
https://en.wikipedia.org/wiki/Tracer_round
http://www.ask.com/youtube?q=How+Can+You+Tell+if+Someone+Used+a+Tracer&v=RZxGKjwz1AI
http://www.techtalkradio.com/techtalk-radio-podcast/how-can-you-tell-if-someone-is-using-tracer-rounds/
https://www.youtube.com/watch?v=yBwHnVbgLkY

What are the dangers of using tracer rounds
One of the largest risks of tracer rounds is that they are a fire hazard. Since tracer rounds eject small amounts of pyrotechnic material, if a round misses its target and instead impacts somewhere else, it can start a fire. In fact, since tracer rounds can ignite combustibles such as gasoline and alcohol, they are not commonly used in war zones.
When a round is fired, it contains pyrotechnic material which may be ignited. If the target strikes the tracer, it can begin a fire.
Tracer rounds will not ignite flammable materials like explosives or rubber, but tracer rounds can ignite combustible materials such as gasoline and alcohol.
When removing or replacing a round from a weapon, make sure that hands are kept away from the muzzle and never point the muzzle towards anything that is stable or flammable while removing or replacing round, e.g. gun bag, cleaning rags, etc.
Tracer rounds are made from slightly different materials than conventional ammunition is, so when handling tracer rounds and conventional ammunition together, you must ensure that you do not mix them or even load them into the same magazine or chamber.
