As a newly-joined member, I keep coming across these old threads that capture my interest. I can't help but ask for an update. Did you solve the ammo riddle? Have you fired this piece yet?
For my own part, I side with the general consensus already offered: The workmanship looks to be excellent, the form is of such unprepossessing ugliness, that it must have a great purpose, because necessity is the mother of invention - and only a mother could find this weapon attractive!