Here are my current singles.

[Linked Image from i.imgur.com]

In order down, they are:

WC Scott high grade 8 gauge Light Waterfowl gun.
Galand Paris 10 gauge waterfowl gun (barrel as thick as a pipe).
Albert Harper Birmingham 12 gauge
Manufrance Simplex Model 26 16 gauge
Bonehill 16 gauge single hammerless with crossbolt lockup.

The top two are Damascus, the rest steel. The Galand I believe is quite early. The barrel is Damascus at the front but the Octagon section is larger and is laminate. I suspect the thicker rear was hammer welded over the inner barrel section during construction. It also has a rear v-notch sight, I presume for vlock shooting. It is too front heavy for much wingshooting.