I've never found one and probably will never find one where I live, but that definitely looks like a reins guide with the threaded stem snapped off. The uneven wear on the inside edges is where the reins rubbed.
I've never found one and probably will never find one where I live, but that definitely looks like a reins guide with the threaded stem snapped off. The uneven wear on the inside edges is where the reins rubbed.