Making a powder horn is not at all difficult. Anyone who has the desire can learn to make very nice horns in a relatively short time.
This page gives full instructions;[url]
http://www.nmroyalrangers.org/FCF/making_a_powder_horn.htm[/url]
Run a search on powder horns, or some such, to find examples of nice designs you might want to make.
Snag,
That's nice work for a first attempt.
Search the web, or look at Track of the Wolf's web page to look at original horns, or reproductions of original horns, to learn more about design features on those old horns.
IMHO, you have the ability to do nice work. A little research and some practice and your horns will look like the old ones.
J.D.