I will believe that burning powder is a light source?
some other hints on this source wiki
There are three types of tracers: bright tracer, subdued tracer and dim tracer. Bright tracers are the standard type, which start burning immediately after exiting the muzzle. A disadvantage of bright tracers is that they give away the shooter's location to the enemy; as a military adage puts it, "tracers work
both ways". Bright tracers can also overwhelm night-vision devices, rendering them useless. Subdued tracers burn at full brightness after a hundred or more yards to avoid giving away the gunner's position. Dim tracers burn very dimly but are clearly visible through night-vision equipment.
some tracer rounds:
Another thing to notice, is that the tracers in Arma III Goes out of view for the player they just dissepear in sight. like something is wrong, they just get deleted after so far distance, this looks very bad.
Look at the video to see how a tracer round slowly fade into nothing " Burning up" As so far in arma 3 they burn and stopp. not slowly fade.
thats something BIS could have fixed easy, and it would make the effect of tracers look much better!