It was badly covered in oxide and clay so I cleaned it up. That's when I realized it was a hand poured projectile with riflings. I have to do some research and get the weight and size. How many rifling marks should be on it?
If there are rifling marks it is not a musket ball, muskets are smoothbore with no rifling. If there are rifling marks, they came from when the ball was fired, impressed from the rifling in the barrel of the gun, the ball was smooth when cast. The number of rifling marks would vary depending on what gun fired the ball.