Someone used a great deal of care in making that horn. It's a beauty!
Here is a quote from William Drummond Stewart's Edward Warren:
"
an over-coat of white blanket with a hood, a leather belt, a broad-brimmed un-napped white hat, my ammunition, and a rifle; a tooth-brush and a mane-comb which I thought least likely to break, were in my pocket, a butcher-knife was in my belt, and an awl was attached to my pouch, which, with a large transparent horn of powder and a wooden measure hanging to it, completed my equipment. (page 51)
The carved and engraved horns get all the attention, but I think it was commonplace back in the day to scrape powder horns thin enough that you could see how much powder was there.
I saw the orientation of the staple, also, and though it unusual. Functional, though.
Thanks for posting!
Notchy Bob