Atmospheric conditions are key to how well the bullet trail is observed.
It takes a bit of practice to recognize what one is seeing. My first observation was a ripple effect that affected the entire field of view of my scope. I was beside the shooter who had commented on the trail from my shots.
Once I learned what/how to watch I could call the shot well before impact. It seemed like everything went into slow motion. He was shooting a 270 Win a long ways in a decent wind. The drift of the bullet was significant. It was easy to observe from about 1/3 rd of bullet travel all the way to the target.
I let him shoot my rifle, 270 AM, so I could observe the differences in cartridge performance. The difference was significant to say the least.
Observing large caliber lead cast bullets traveling away from the sun is impressive. The shiny base is clearly observable all the way to the 200 meter rams.