That's a good observation, Terry. "Not for ball" went away when the fractions were adopted. Of course you could look at a lot of "not for ball" guns the bore diameters of which didn't fall within the fractionalized parameters. In other words, they might have really been 12's rather than 12/1, 13/1 etc. And a lot of the "not for ball" guns that were marked with fractions as a result of reproof may not have started life that way, with the change being the result of honed bores.