Just brought home a new double, that for me, checks all the boxes: 16g, snap action, Damascus tubes, cocking indicators, respectable wood and a breath over 6 pounds. It does have an ill-advised recoil pad and some buggering to a couple screws, but overall in excellent shape. I would date it no later than 1887 based on the "not for ball" marking on the flats.
I know nothing of the maker, having only seen a couple others on the web. I'd be curious if any of the experts here know anything of the company. I'm wondering if the gun may have actually been made by T. Watson as the action has a "T.W. Patent" stamp on it.
Here are some pics:
