We recommend the tension on the throw lever to be set tight enough to secure the mount to the rail without any movement, but not so tight that you have to pry the throw lever open with a tool to remove the optic from the firearm. This is set by adjusting the tension in with the adjustment nut. You will want to feel resistance on the throw lever at about the 2/3rds closed position. Please ensure that the flats on the adjustment nut line up with the adjustment nut pocket in the mount itself. If the flats on the adjustment nut are not lined up correctly, the adjustment nut can become wedged in the pocket and seize up. To un-seize the adjustment nut, you will need to open the throw lever assembly completely and tap the throw lever with a rubber mallet. This will un-stick the adjustment nut from the pocket and allow you adjust the mount tension.