Colt Model 1855 conversion of a half stock sporting rifle to cal 45 Colt

Colt Model 1855 conversion of a half stocksporting rifle to cal 45 Colt     Serial 159,  probably done by a gunsmith, but could be a Colt Factory try out. 

25 inch part round, part octagon barrel, deeps rifling, excellent bore, the cylinder is 43 cm long, frame and topstrap have been professionally shortened, stock is numbered and original to the gun and in fine shape, works perfect, no markings except for the serialnumber, Defenetely a colt product, but never seen another one but this one.  Good shooter.