Battle,
It would be helpful if you would post photos of all the markings, especially proof marks and any markings on the breech face. You will need to remove the barrels to do this. I don't estimate the value of someone else's gun that I don't have "in hand". I will say that it looks like a very interesting fun gun. However it will be a handloading project or expensive custom loaded ammo must be found. The 5.6x35R Vierling is close enough to the 22 Hornet( 5.6x36R) that Vierling cases can be made from Hornet cases by thinning the rim and trimming to length. Brass 24 ga. cases are available, from MagTech( I believe).
Mike
