A couple of months ago I bought a Lee 2-cavity .490 round ball mold. I've cast a couple of hundred balls and they came out fine. Today I decided, out of curiosity, to check them with a micrometer.
They vary in size from .478 to .484, and are out-of-round! I could not find one that was .490. I then checked balls cast from my other Lee molds - .440, .445, .451 and .457. All are within +/- .003 of the stated size.
Most peculiar. I've emailed Lee and am curious to see what they have to say (particularly as I'm in Australia, where it will cost more than the mold is worth to ship it back to them!).