I hope someone will be able to shed some light on the matter. I bought the bayonet from a auction in Canada but I live in Ireland! I think this is a 2nd issue Brunswick Volunteer bayonet, but has a modification which I can not find a reference to. Overall length is 26.75" or 679mm blade length is 22.1" or 561mm. The side of the grip with the mortise slot has been flattened and counter stamped.with the mark N S over 51 over 8 would like to know which unit this is. Same on the otherside of the grip but this time its B over underscore 174. On the pommel the number 34 and also six lines in to lots of 3. I might have this wrong as to the bayonet type! maybe it was modified for some gun from the US civil war? Yet again any help most welcome.....paul.