Well, I have to eat a little bit of my words. I was watching 'Battle in the Air' on THC last night and was poaying close attention to the tracers from the gun cam footage. I'll be dammed, they do end up in pretty visible spirals. I will try to describe them as best I can. usually one is watching for the hit/miss or damage effect from the round, so it is easy to miss the phenonemenea (fuhh-nom-uh-nuh) that happens to the smoke from the tracer.
the smoke is straight for approximately 2/3rds of the visible tracer round, however, if you watch closely to the trailing 1/3rd,
it developes into a wispy spiral right before it dissapates into the air. it is like the "Life of a Tracer Trail". The entire tracer trail maps out, what i believe to be a conical (probably parabolic) helix with the spiraling effect only visiable (vizz-uhh-bull) at the trailing 1/3rd of the entire tracer trail. The spiral seems to develope as the trail loses its E and gives up the ghost. Very interesting.
I would say difficult to reproduce.
