Barry C. Wood in Painted Post NY. Active 1842-1876 and maybe later. Swinney says he was born in 1817 and was still alive in 1891. He appears to have been a prolific maker - the Swinney book on NY gunmakers devotes 6-1/2 pages to him.
My experience has been that when rifles of this period show up in British auctions, more often than not they are in excellent condition. That leads me to think they may have come home with British visitors to America n the 19th century. We know from American sources that British visitors, attracted by the hunting, were fairly common. A friend of mine went to the Holt's sale and bought the rifle you showed here a few years ago. I saw it shortly after and it seemed to fall into that category... well taken care of but rarely shot.