Scott, for what it’s worth, I have 5 or 6 similar horns down in the shop that I don’t know what, if ever, they’ll get used for. I bought them on eBay, and I don’t know what sort of cattle they came from, but they are extremely thick, and have large ridges in the interior like yours. I’m thinking of making a hunting horn from at least one of them, it’s certainly large enough to have a good sound (I think), but I don’t know if any will make a decent powder horn. They might all get cut up for knife handles, or for turning tips from. At any rate, I’ll pick my horns out in person, at shows, from now on.
Greg