Hello, Michael! Thank You for sharing this. This weapon has really strange shape especially the shape of the stock. It seems that stock is product of recycling of broken lance
I think that the shape of the rear end of the stock may be a hint for a more correct dating. Of course, only if it's really part of the lance. Else I want to say some word about bulge behind the touch hole. It's not unique. I know at least one more barrel with the bulge of absolutely similar shape (look at attachment(Length: 14,8 cm; Caliber: 19 mm; Weight: 2,5 Kg))