See pics of an early (what indicates may be) Belgian made Double-Action revolver. It appears to chamber a .38 S&W cartridge nicely. It is a bit of a contraption and the break-down is a peculiar Un-Screwing of the Barrel and Cylinder Assembly away from the breach-face when 1 screw is removed...
There is a number "17" under base of barrel and stamped inside grip frame. The Grips are Horn of some sort. A strange little animal for sure (and not very nicely machined inside)
My guess is very late 1800's. I am curious for Anyone to jump in here and fill in with any information / knowledge they care to add.