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How to Adjust a Number 4 Peep Sight

Number 4 peep sights are adjustable sights that where commonly found on bolt action training rifles, primarily the Mossberg model 42, during the Second World War. Chambered to use .22 LR ammunition, these rifles were produced for the British army and equipped with adjustable peep sights, similar to those on Lee Enfield rifles (the standard rifle of British army at that time). The advantage of the number 4 peep sight is that it's adjustable by hand.

Things You'll Need

Target
Ammo

Instructions

- 1
  Set up a the target at a range of approximately 25 yards.
- 2
  Estimate the necessary adjustment to your sight by firing at least three well aimed bullets at your target.
- 3
  Mark the center of your shot group on your target and determine the necessary corrections. For instance, if the center of your shot group is 1 inch above and 1 inch to the left, then you will need to correct your peep sight 1 inch down and 1 inch to the right.
- 4
  Use the knob on top of the rear sight to adjust the elevation and the knob directly next to the peep sight to correct for windage (horizontal movement). The knobs are calibrated to move 1/8 of an inch, for a target set at 25 yards, for every "click" of the adjustment knobs.

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