[Vermont Lt]

It sounded like, well, a bullet--very fast, cutting the air when they went over my head. No boom. No hollywood richocet.

And yes, you drop to the ground involuntarily. In hindsight, I realize you need aboslutely no training. You hear that noise and your face is in the dirt. Its kind of funny now. Wasn't then.

[Indie]

The best example of the sound can be found in the movie "We Were Soldiers" with Mel Gibson. Exact. Rent it and be impressed. Besides it's a darn good movie.