My grandfather gave me this sight many years ago. It turns out it fits my T/C Seneca, but that wasn't originally what it went to. The mounting screw is not completely round, sort of oblong. Elevation is done by loosening the nut and turning the whole sight up and down. Windage by the square nut. My grandfather told me that it was very old. It's not anywhere in Stroeble's Old Gunsights book. I was told at one time it was for an original Hawken, but have no way of knowing. Has anyone else seen one like this?