I color my bullets with 4 different color sharpies and note it on my load data. Also note where it hits. Shoot white paper and you can see the colors easily on the bullet holes.
That's a neat piece of info. Will have to try it.
Even with good glass, if one has a really tight shooting gun, sometimes a 4 wheeler trip (or several) to the target becomes necessary to property label each hit.
The hits I can ID, I typically label on a tablet at the bench, drawn to duplicate the target.
DF