I wonder if it was a variation of this
https://www.google.com/search?q=vin...ayVNXKBtCToQSIgoGABg&ved=0CAYQ_AUoAQ#imgdii=_
doesn't look like anything in those pics looks more like some kind of pin for top of scaffolding or something the hole in middle would be for a smaller pin to lock together
For context: It was in an 1874 Cavalry Camp area. Antone could have come by and dropped it at any time though. Sword hanger?
There's not a side of it I would consider sharp or previously sharpened.
Nor sure about the nail puller (or fence staple puller maybe), seems a little frail to be hitting with a hammer. Looking...