If you've ever looked through a spotter scope and watched a bullet cut its way through the air, you've seen Bullet Trace. If you can see it, you can film it, and you can definitely use it for shot review.
Capturing bullet trace is actually pretty easy.
Once you've mounted your camera or phone or what have you to the eyepiece of the spotter scope, you can apply the real trick: Put the spotter scope as 'in line' with the barrel as possible.
Try to position the spotting scope so that it's a few feet behind the shooter, over the right shoulder or left shoulder (if they shoot left handed). Then, try to raise or lower the scope so that it's roughly level with the rifle's line of bore.
Of course, the shooter gets in the way sometimes. We can get pretty close, though. This is one of those times where 'close' is often 'close enough.'
Depending on the weather conditions, it could get even easier. And the farther the bullet travels, the bigger the round, and the faster it moves (especially when supersonic), the more distinctly it stands out.