[Poltava]

I've both fired tracer, and seen tracer live, fired in war time, and I think that the spirally thing is partly an optical effect: especially when firing from a moving platform, the tracer will appear snaking or moving in spirals relative to the position where you are. Especially in the night time, tracer takes on all kind of strange shapes, especially viewed through an image-enhancer. Still the basic ballistic geometry is about a projectile moving in a arc. So if you see it straight from the side, and both the firer and the target is fixed, it will be pretty much a straight band. (Tracer bouncing, like it can do in IL-2, and going all crazy here and there, is very common, IMHO.)

Still: it would be a nice mod, not because it's more "realistic" but like that prop-mod because it gives a visual effect that we expect from seeing a lot of movies.