98sahara:  Your Grandfather's Krag has the 1901 Rifle sight.  The elevation graduations go to 2,000 yards in the raised position.  In the 'ladder down' position, the graduations on the side of the base (ramp) go from 100 to 400 yards.  The sight is adjustable for windage.  The lever at the front of the sight base swings to the left to loosen tension.  The upper part of the sight then pivots on the front sight screw.  If you swing the lever to the right, it again tensions the upper part of the sight to the base.  You may have to spray some penetrating oil on the sight to loosen up parts.