New Hammer Gun - What did I buy?

Try Track of the Wolf, Dixie Gunworks, and so on -- they're all on the web.

You need the dimensions of the inlet lock mortise and the hammer throw to order a lock and hammer that will fit.

You'd have to ask them -- I wouldn't send the lock blind and I'd insure it, you might never see it again.

You have a gun retailed by H&D Folsom, A very large sporting goods supplier from the early 1900's to the 1930's. In this case it is listed as being made by Crescent Firearms Co., which is not surprising because Folsom owned Crescent at the time. Being an outside hammer gun it was probably made in the early 1900's. The steel used in these guns was much different from modern steel and after a hundred years who know what changes have taken place internally. You say it is a single shot. I hope you are not using modern High Pressure shells in it. If you are, count your fingers and eyes each time before you shoot it. Sooner or later it is going to blow on you, maybe not today or tomorrow, but it will go boom. If you shoot it at all you should use only those shells that it was designed for, black powder. For parts, e-gunparts may have some parts, also try Dixie gun works, they have generic hammers that may be adaptable. Good luck and please shoot safe.

You might also want to try Numrich at www.e-gunparts.com.

Ahh, here's the linky-thing directly to the list for American Gun
http://www.e-gunparts.com/model.asp?idDept=8

They even have a schematic for outside hammer guns.

I'd recommend having a good gunsmith give it the once over and do any of the repairs. To me, it's one thing to change the barrels or swap out internals on a modern Remington 870 or Mossberg 500. It's a whole other animal to try to repair a ~100 year old gun that may or may not be safe to shoot.