muckmaw said:Having never seen a real tracer trail...I'll have to take your word for it that this is what they look like.
I never have, either, and I've shot many different MGs. I've also been shot at by a bunch of Soviet-bloc MGs, and they didn't leave smoke trails, either. All I've seen in real life has been the fire of the tracer element itself. The recent war with Iraq was all on TV--how many smoke trails did you see?
The only context in which I can remember ever seeing smoke trails is in guncam film from the early war, like the BoB. Brit tracer of that vintage, at least, left spiral smoke trails exactly as you see in these shots, although I can't recall seeing it in German film of the same vintage. But certainly by later in the war, German guncam film doesn't show the smoke, and I can't think of any US guncam flim that does. And this applies to film from ground battles and light ack vs. air attack as well.
So it seems to me that smoke trails existed early in the war, at least for the Brits. But it didn't take long for everybody to develop smokeless tracers, which is what we still have today.