My chart shows it's a Sentinel and should fit a 2" J frame. The "B" indicates it's black and 815 is the model number. Can't help with when it was made but I'd say the sixties or earlier. Can you post a pic? Hope this helps.
Hi Rodger, I believe your holster is a "Combat" made by Bucheimer Clark in California, Model 13A. The different models have different numbering schemes. It is in the 1975 catalog. The Sentinel was made earlier by Bucheimer in Maryland.