I just added a .69 caliber "belted ball" to my collection. Most of these I've seen, I have not thought were real; many don't have much patina; or many are simply miscast round shot with a wide seam. Besides that, they were not used during the American Civil War. The two-groove Brunswick rifles used in this country during the war used simple ammunition (without the "belt").
I acquired the one shown which have an honest patina. This came from the Crimea which is where they were used. And best of all, it was not expensive.