Take it to a reputable gun smith that can see what you hve and tell you what it can safely shoot, if anything.
One issue is what type of ammunition may safely be used in it and your post gives us no idea of its gauge (12, 16, 20 and etceta) or the length of shot shell for which it is chambered (2-1/2", 2-9/16", or 2-3/4"). The old a gun may be a 2-1/2" or 2-9/16" when sold, but someone may have reemed out the chamber to take a larger shell.
Just because the round fits do not assume that it is safe to shoot. Chambers are machined to allow the petals of the shell to open within the length of the chamber. If they open beyond the chamber barrrel pressure may rise to an unsafe level.
Since you seem to be guessing about its age, it is possible that it has a Damascus barrel and they really need to be checked by a competet gun smith for safety.
You should also be careful using modern loads, such as magnum loads.
Then, given the passage of time who knows what may be wrong with it!
Like jaguar says, take it to a competent gunsmith.
Last edited by TheKlawMan; June 29, 2012 at 05:17 PM.