Just had a look at my notes I used to shoot a Martini ISU all I have is if zeroed at 25 yards the going up will put you near enough on the Bull at 50 yards also when you want to adjust go the opposite way to Anschutz sights i.e. turning the elevation wheel clockwise will raise the fall of your shot turning the windage wheel away from you will move your shot to the right,,beautiful rifles to shoot,you could also try James Hallam of the classic Gun Company of London for parts,