strange it has proof marks for both black powder and smokeless
either its made at that period when it was changing over
or its a replica
and i'm leaning for that time period , figure that time in belgium and you'll get a approx year of manufacture
the change over was fast in many places . 4-10 years i read once
ongoing in others it also said
old article from the late 30's
have no idea of value i think its a parlour pistol
its a rook or flobert style action
i'd try a .22 short very gently in a safe area as thats what many where meant to shoot , .22 caps where common too
it something wont go in gently , dont force it
go up to a .22 LR to see , but i'd only use CB caps if i was to shoot it myself