your rear sight should have a small screw with a sliding piece that allows you too adjust your back sight ,, move it down a bit , if your elevators all the way down ,, wade
To move the impact at 100 yards on a Marlin rifle with a 20" barrel requires .006" of sight change. (front or rear)
For example:
If you are shooting 6" low at 100 yards, your front sight needs to be "Trimmed" .036" shorter or the rear stem turned up 1 1/2 turns.
If you are shooting 6" high at 100 yards your front sight needs to be .036" taller or the rear stem turned down 1 1/2 turns. (If your stem is already at the lowest position a taller front sight is required)
If you are shooting at a shorter range than 100 yards adjust accordingly.
50 yards = 2 times the change needed. (.012" for 1" correction)
25 yards = 4 times the change needed. (.024" for 1" correction)



























