Tool-less re-zero adjustment knob for aiming devices, and methods of zeroing an aiming device

In an aiming device, a user-zeroable adjustment knob, comprising:

• a rotating member rotatable about an axis of rotation to change a setting of the aiming device;
• a dial selectively couplable to the rotating member via a clutch for co-rotation with the rotating member, the clutch being disengageable to allow the dial to rotate relative to the rotating member for zeroing the adjustment knob without changing the setting;
• and
• a locking mechanism that prevents the dial and the rotating member from rotating relative to the aiming device when the locking mechanism is locked, to thereby inhibit inadvertent adjustment of the setting, the locking mechanism including a lock release movable relative to the dial and the rotating member to release the locking mechanism and allow the dial and the rotating member to be co-rotated to adjust the setting.