Is this object a U.S. Civil War grenade?

I was looking around on a sand bar in the Mississippi River. Just wondering what this is that I found. It was found just a few miles south of the area where the battle of Belmont was. I thought maybe it was a used grenade, or is it just an odd shaped piece of metal?

Thanks,
Ryan

? ? ?

Congratulations. You’ve managed to stump the editor of Civil War Times. Frankly, I’ve never seen anything quite like that thing, but I can only say that it is too small to be a grenade.

Sincerely,