I'm sure there is an "expert" out there that can "prove" that round balls have to be perfectly round, and smooth, and the sprue must be completely removed, oh, and they must all weigh the same as well, or they won't fly true. In my experience any advantage in all this is negligible. I have a bunch of old bullet molds, and none of them throw a true ball. In fact some are so out of round, they won't even roll straight. People fed their families, fought wars, and won target matches with such balls. Shoot 'em and enjoy 'em.
Hungry Horse