T. Dumoulin (Belgium gun maker) made firearms between 1880 to 1940). Marked with the diamond/12 C on the barrel, has been used since 1898-1924 applied to shotguns given black powder proof. This shotgun’s barrel is marked “Fine Damascus Steel” and is a double barrel, double hammered and double triggered.
(The) “Interchangeable” model is a Belgium Twist barrel and was know as the “Star of David” brand, There were several Dumoulin gun makers located in Belgium around Leige.
Sold “AS IS” given that the breech lock does not lock (spring may be broken or non-functional. Right hammer is loose and will not positively engage into the full cock position. L firing pin lock is broken. From the research, these were clones and there were several Dumoulin’s in the Leige, Belgium province. T Dumoulin appears to be one of the lesser known and collectable gun maker of the period.