Ignoramus6213 wrote:

I was at a gun range today with a friend, shooting a 9mm hand gun.

When he was shooting, I was standing behind him, watching. After a few
shots, I realized that I may have seen a glimpse of the bullets as
they flew downrange.

I watched some more, and it did seem this way, although it was hard to
see them and the barrel flash did not clarify things.

You are probably seeing the distortion in the air cause by the
shock wave radiating out behind the bullet. That is a much larger
phenomenon than the bullet itself. If the light is polarized,
as when reflected off water, windshields, etc. it turns the range
into a Schlieren camera which easily detects variations in air
density, and would make the effect much more visible.

Jon