F. Dumoulin & Co. 20 Gauge External-Hammer Sidelock SxS, 26 in Barrels, Cylinder/Cylinder, 2 3/4 in Chamber, Belgium
This Belgian-made F. Dumoulin & Co. side-by-side stands out as an external-hammer sidelock with classic field features and ornate stock work. It has 26-inch barrels with fixed Cylinder/Cylinder chokes, a 2 3/4 in chamber, and a matted solid rib topped by a brass bead. Decorative hardwood furniture with an openwork skeleton butt and hand-cut details highlights its Liège craftsmanship.
Condition
Overall Condition: Poor condition.
Bore Condition: Poor - Noticeable dirt, stains, significant corrosion or damage.
Specific Condition Notes: The barrels show significant handling and use marks. There is a dent in one barrel that is visible from inside the bore. The left-side firing pin appears broken. The barrels fit loosely to the action. The firearm is not safe to fire in its current condition and requires gunsmithing for safe operation.
It is recommended for display only.
What’s Included
- F. Dumoulin & Co. 20 Gauge external-hammer sidelock side-by-side shotgun
Built in Liège, Belgium by F. Dumoulin & Co., this external-hammer sidelock features a traditional top-lever action and double triggers. The matted solid rib carries a small brass front bead for a clean, unobtrusive sight picture.
The 26-inch side-by-side barrels are fixed Cylinder/Cylinder, matching the requested "Cyl Bore" detail, and are chambered for 2 3/4 in shells. Capacity is two rounds.
The hardwood stock is a notable highlight, with an openwork skeleton butt, hand-cut checkering, and relief carving. A white diamond inlay accents the splinter forend, and the textured buttplate completes the look. Length of pull measures 14.0 inches.
External hammers with checkered spurs and double triggers provide a classic, mechanically straightforward control layout. The single brass bead front sight complements the matted rib for quick alignment.

