12 Gauge "Long Tom" id help

[Gun5tuff]

My wife's great grandfather's shot gun is still in the family. There is only the name "LONG TOM" engraved on the left side of the action. It's a single shot 12 guage with a 40" barrel. It has an external hammer. Under the fore stock and on the forestock is stamped the following:"F I" and "310". On the top left side of the barrel over the action is engraved "12 GAUGE". The metal is browned rather than blued. The age of the gun is at least 1897 when the grandfather inherited his dad's farm and the gun.
Would anyone have any information on guns of this type?

 

[North of 58]

The Long Tom trade name was used on shotguns made by the J. Stevens Arms Co. for Sears, Roebuck & Co. Thats about all I know about them. If you google either name with Long Tom you should find more information. Good luck and let us know what you find.