Here's a chart posted by Zonie back in 2011.
The whole thing can be found in the thread "SHOT (pellet) SIZES.
Another evidently knowledgeable member, the late paulvallandigham, pointed out the "Rule of 17" that I was not aware of. It says subtract the number of the shot/pellet from 17 and you get it's diameter in hundredths of an inch.
Good stuff to know!
