A friend call and said he would bring his 13-2 to the show for me to check out. He was having intermittent trouble opening the cylinder. I was expecting a troubled basket case but it was a beautiful 4" example that had been fired very little over the years. All it needed was a light cleaning of the action with some fresh lubrication. Now it feels like a brand new gun. The thing that has me puzzled in an N on the barrel flat. It's an all original blued gun and the N does not show up anywhere else. My nickel 13-3 and -2 both have the N on the three normal places. I can't figure out how that N got stamped on this blue gun.