Still hunting in the same area as all the other civil war history I've found. I've found many projectiles, but never any this small. I have the book Civil War projectiles II: Small arms & field artillery, with supplement, but couldn't distinctly identify it. Thanks for any insight gentlemen..
I can't entirely tell from the photo, but if that is vertical lines in the upper groove, then it's 100% modern as that process wasn't used until post-war.