While I can agree with Don that the tip is too much horn to use in a powder horn, I would hate to see the rest of the horn used for a drinking mug, altho' that is often what you see these long horns made into in Europe.
Mostly, I don't think I would want to carry all that weight around as a powder horn. The tip can be cut off and used for a variety of articles, including a powder measure. That long curve makes this a good candidate for a powder horn that will wrap around your hip or side. I really would like to see that ragged base saved, with some kind of plug put inside it, leaving the ragged edge to be decoratively filed and shaped, and hole cut in a " lip " to use to hang the powder horn strap at that end. Carrying more than 1/2 pound of powder gets to be a really " drag ", in more than one way. Wiht all that solid horn available, you could do some nice reduction and ring work on that neck. Ou might even consider making a fish mouth towards the front so it looks like the neck is coming out of the mouth to pour the powder. ( Maybe like a long skinny fish like a Northern Pike???)
Just some thoughts.... That is a beautiful horn to work with. It is just NOT going to look like more traditional powder horns, that are shorter, and wider around. So, don't try to do so.
Best wishes. :thumbsup: