Hello, I'm hopin' for some help id'ing a rear sight that I bought. I was rummaging through the junk drawers at a local shop and picked up rear sight. It was in with a bunch of 30-40 Krag stuff. It's in very nice shape. There is a lever at the front of the sight base that when loosened allows the rear sight to pivot in an arc for windage adjustment When you tip the slide up there is a notch on top and a peep on the bottom. I know a picture would be better, but when I put my card in the reader, I keep getting box saying the disc isn't formatted. But I also can't format it. Catch 22. No markings other than distances. Graduated from 1 to 20. Does this sound familiar? Thanks
THD