They look like they do in the films in IL-2 I know for sure. The only tracers I have ever fired were from a .223 in the river bottom at night, and others in this thread have nailed it. You see just a glowing dot, not a streak. The shaking you see in the films could also be from the recoil from the guns. My 25-06 has a pretty decent recoil, I cant imagine (6) .50s all firing at the same time. That thing had to shake like a dog passing a peach seed.