I've seen something, depending upon the light and background, but I'm not sure it is actually the shot cloud, or a refractive disturbance that occurs when the shot cloud drops below the speed of sound. As you said, I don't recall seeing it when I'm doing the shooting.

I do know for sure that you can see large caliber bullets at low velocities, such as .45 cal. pistol target loads, when the light is right.

A true sign of mental illness is any gun owner who would vote for an Anti-Gunner like Joe Biden.