An atmosphere actually holds a suspension together until a current (wind or just Brownian motion) disperses the suspension beyond visual acuity.
This is a messy scene. A semi-fluid tungsten-steel kinetic round impacts an unarmored individual at 3000 meters per second. The round is fired from above, impacts the shoulder at a thirty degree angle to the body, and, more or less, rips him in half as the round spreads out. He doesn't gib or fall into halves exactly, but the overkill here is excessive.
I think I'm going to go with a bright red frozen splatter for now. In fact, come to think of it, any 'vapor' is just going to spread along the ground until it freezes as well. There's no atmosphere for it to suspend in. There would be some vertical motion due to heat, of course, but that certainly won't last long. Hmm. Need to think on that some more.