Roy, the "interchangable" suggested that the parts had a high degree of interchangability and could be simply changed in the event of breakage (requiring little to no gunsmithing), like Parker and L C Smith
This is from memory, but I believe Doumlin helped set up an exchange, SPI, that made parts with a high degree of interchange. (Not implying this is gun is a product of that exchange.) Funny how this is used as a "put down" by some. Today, we simply refer to this same manufacturing strategy as OEM.
This gun was made some time between 1898 and 1924. I do agree it is a JABC. Who ever worked on this never even put their trademark on it. Not a lot of pride in workmanship...
Pete
