This belonged to my mother's friend's husband's father (quite a mouthful) and looks like its going to be fully restored by him to pass on as a family heirloom. Wonder if I could get some details on the piece:
There's probably a 23ZS inside, or maybe a 1x.68 of some sort (12.68 or 10.68) - either way it's a nice caliber from the 50's. A long shot would be a 22LS. It's already been redialed once so it won't hurt to do again if necessary. Pop off or screw off back?
Don't have any more pics just yet, the dial was my biggest question, if its not original the discolouration would be worth correcting.