Yep-Stoney56 is correct
A 3 ringer- CW era(doesn't look like an Enfield-). Many years ago I bought a great book "Civil War Projectiles 11-Small arms & Field Artillery". Before I bought the book I thought all mine balls looked alike. It was fun going back to my mine collection and finding exactly who made them and in some cases Federal or Confederate.
You might want to go back to the site and look some more. CW camps were all over the north(camp or firing range?)
George