Here are two more nice doubles coming up at Poulin Auctions 2018 Fall sale, which starts this Saturday, 10/20.
This Lang is a converted pinfire and an interesting piece of history. Lang was one of the first British makers to build breechloading shotguns, and I bet this gun was among the first ones he built.

LOT 1015: 10g JOSEPH LANG UNDERLEVER HAMMER SXS SHOTGUN
This little Francotte is in great shape, but because it has been redone (very well, btw), it should go for a very fair price.

LOT 1055: .410 FRANCOTTE BOXLOCK SXS SHOTGUN
Check out this video to learn more about each one and to see the guns close up.