This swivel does have a unique trigger mechanism. This trigger works the same as in my last post "Ohio I & II" When the trigger is in the fired position it is to the rear. The center position allows the hammer to cock. With the hammer cocked you have the option of rocking the trigger forward till it clicks, then it rebounds to the center position at that point you have a "hair" trigger.
In Donald Hutslar work "Gunsmiths of Ohio" he shows David Rose in Liverpool Ohio in 1853, then in Rawsonville Ohio in 1859 and finally Grafton Station Ohio in 1860.
Ned Roberts book "The Caplock Rifle" lends me to believe that percussion doubles were popular in the post Civil War period. I think that this swivel is probably a later build than the rifle in my previous post "Ohio I & II" and it is marked Grafton Station.
Over the years I have seen a lot of percussion double rifles (not swivels) that were New England products. Just the ticket for black bears?
Thanks tim