I recently acquired a rear sight at a gun show that the seller claimed was an Enfield muzzleloader (Civil War era) rear sight, but I have no pictures to help me identify it for sure. It has a crown proof mark on it and the sight is a ladder with a slide on a stepped base, The biggest mystery to me is why the back of the leaf is marked with upside-down range gradiations from about 1500 to 2000 yards. Does anyone out there know why, and if this is indeed an Enfield rear sight? I would muchly appreciate any input. - Eric Smith