Al
Some cannon balls used were that small,here's a pic of one found in Louisiana,but with your ball being of an oval shape I would say that it was used in some type of grinding process,like coal.
When you have an artifact of iron,don't never,ever,ever use a file on it.I can show you the electrolysis process that will take the rust off
This item most likely came out of an old ore crusher. I have seen similar ones where old mines had crushers set up to pound rocks into dust so they could extract the minerals out. They would have a large rotating barrel with a bunch of these inside to pulverize the rocks taken out of the mines. They didn't want perfectly round ones, since odd shapes tended to tumble better. You might check with a mineral museum like the one near Cartersville. I think it's called Wienmans Mineral Museum. Just off 411 heading towards White.
yes, a ball mill used Iron balls to crush rocks. After years of service they looked similar to what is in the picture. Saw some years ago at an old iron mine that had been closed for a long time. Old machinery was strewn all over the woods near the old site. Saw some at an old lime quarry site also.
Looks like pig iron to me. I believe they used to drop hot iron in water to cool it and at the same time it would form a ball such as they made lead shot.
i found one like that metal detecting up near lafayette i was told that it was used in milling or rock crushing as polaris30144 said,one thing about them they will sure make a metal detector sing
If you think it might be a cannon ball just take it up to Kennesaw Mountain and ask. If they don't know then sureley thay can get you pointed in the right direction...