I answered a question today for my friend and fellow detectorist Mauthe. About musket balls so I thought I might do a mini informative on them. Yes,
old musket balls come in all sizes. I am going to concentrate on the common ones up in the midwest. The buck and ball combination. The best way to tell if the lead shot is old is too look for a sprue mark, weather it was rounded off or not, the seem or dimple will
always be visible when cleaned up a bit if the ball was not shot, or didn't have a solid impact. The sprue is the lead piece cut off when the balls where in a mold. If it has one it is an old musket ball. Now you southern folk are going to have a lot more info than me, but the sprue is the indication of an old musket ball.
Below is a drawing of cast balls with balls attched by their sprue.
Below is a Buck and Ball most times you will find the smaller or larger sperated pieces, they will only be together if a paper cartridge disintegrated.
Buck and Ball "cartridge" below:
Hope the info helps!