How To Adjust Sights/Scope (Without Wasting Ammo)

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    • #105979
      Brian from Georgia

        As a rifle marksmanship instructor, I often find that even long-time shooters don’t know how to efficiently adjust their sights or scope. Here’s a little primer on the process.

        Many military pattern rifles such as the M1A and AR-15 and most scopes use repeatable “click” adjustments for moving point of impact (POI) to point of aim (POA). These are most often graduated in MOA.

        What’s MOA?
        MOA, or Minute of Angle, is a radial measurement used in sight or scope adjustment. It’s used on rifles because it results in an appropriate scale and an easy-to-remember and practical formula. It is approximated as:

        1 MOA = 1” at 100 yards

        So if you are shooting at 100 yards and your POI is 4” low, you would adjust your rear sight up 4 MOA. POI 6.5” to the left? Adjust rear sight 6.5 MOA right.

        An MOA is a unit-less measurement, meaning it’s the same at any distance. That’s why it’s handy on graduated sight/scope adjustments.
        1 MOA = 2” at 200 yards
        1 MOA = 3” at 300 yards
        1 MOA = 4” at 400 yards
        Etc., etc.

        How many MOA per Click for My Rifle Sights or Scope?
        Click graduations differ for every combination. AR15 iron sights can range from 1/2 MOA to 1.6MOA or more. Sight radius (distance between sights) and type of sights can affect this. You can look up your nominal values, but they are nominal (not necessarily accurate).

        Scope adjustments are generally graduated finer than irons. Your typical hunting scope is ¼ MOA per click, meaning POI will move ¼” at 100 yards per click. Some target scopes are finer at 1/8 MOA and some tactical scopes are coarser at ½ MOA, and even those numbers are nominal.

        You need to determine the click graduations for your particular combination.

        How Do I Determine My Click Graduations?
        This is a pretty straightforward test. Remembering our handy formula
        1 MOA = 1” at 100 yards
        Lets’ set up a target at 100 yards. Do these steps.
        1. Shoot a group.
        2. Adjust 10 clicks up (or down, doesn’t matter – just record which way you went).
        3. Shoot a second group.
        4. Measure distance between group centers. Record the number.
        5. Divide the distance between groups by 10 (the number of clicks you moved it). Now you have your MOA-per-click value for elevation. Record this.
        6. Repeat steps 1-5 for windage
        7. Put a sticker on your buttstock with these accurate click graduation numbers on it, or in your rifle data book.

        Why Is This Important?
        Knowing your click values is important so you can make quick, accurate adjustments without wasting shots.

        A Practical Example
        Let’s say we ran our test on a tactical type scope. The owner’s manual says windage and elevation is ½ MOA per click, but our test revealed that it’s actually .3 MOA per click elevation and .4 MOA windage.

        You and a buddy set up a freshly painted steel target with nice bullseye at 200 yards. He has a good spotting scope. You take the shot and it strikes low and to the left. He knows the size of the target, scales and guesstimates that you hit about 5” low and 3” left. How do you adjust to get the next shot on the bullseye?

        Step 1: Convert inches to MOA (remember 1 MOA = 2” @200 yards)
        Elev: 5” low at 200 yards = 5/2 = 2.5 MOA
        Windage: 3” left at 200 yards = 3/2 = 1.5 MOA
        Step 2: Convert MOA to clicks
        Elev: 2.5 MOA / (.3 MOA/click) = 8.33 clicks UP
        Windage: 1.5MOA / (.4MOA/click) = 3.75 MOA RIGHT
        Step 3: Make adjustments (round off)
        Elev: adjust 8 clicks UP
        Windage: adjust 4 clicks RIGHT
        Step 4: Take the shot
        If your spotter was accurate, your math is good and the wind didn’t change, you should be close to bullseye
        Step 5: Shoot a group to confirm and record final scope settings for this zero

        I hope this was helpful and not too sophomoric.

        Would anyone like to see threads on Battle Sight Zero, Range Estimation, Come-Ups and that sort of thing?

        Brian from Georgia
        Project Appleseed Instructor

      • #105980

          Good stuff. Some optics work in mil adjustments. For example, mine adjusts in .1 mil clicks. 1 mil = 3.67″ @ 100yds or 10 cm at 100m. So, that means 1 click (.1 mil) = .367″ at 100yds or 1 cm at 100m.

        • #105981

            Thanks Brian! :good:
            Dont hesitate to post these kind of tutorials.
            As our traffic is growing every day many viewers will benefit from them even if they seem basic to you

          • #105982

              One tip that has nothing to do with math but a lot to do with sloppy adjustments on AR iron rear sights. Turn it a couple of clicks past where your adjustment should be, then wind it back to the correct position. It takes out the slop and gets it closer than the regular way.

              We saved a lot of time and ammo zeroing once we figgered that out. :-)

            • #105983

                Clicking 2X what you want, then coming back 1X works not only for iron sights but scopes as well. Everything is not always perfect, even with quality optics.

                Similarly, it’s usually best to move your POI too far when adjusting, then come back a little. Aside from the prior advantage, this ensures that you’ve really moved an adequate amount. I know, it sounds silly but really works on the range.

                Good practices overall.


              • #105984

                  Great article Brian! :good:

                  “F”, do we have a “sticky” section for articles like Brian’s?

                • #105985

                    Johny ,

                    yes we can sticky things..

                    Since so much on this board is of a reference type if we sticky everything good we would ahve the entire first page of a given sub-forum as stickies :)

                    Currentyl debating if we should keep stuff like this here or move it to “Articles”

                  • #105986

                      Just a suggestion, maybe a DIY section. On any forum I go to I always click on the DIY section first. My theory is: Why reinvent the wheel. ;-)

                    • #105987

                        I really like to bore sight using a laser first. It gets things fairly close and makes zeroing much faster and I don’t waste ammo. This is all good info too!

                      • #105988
                        Brian from Georgia

                          Bumping an old thread – since there’s been recent talk on long range shooting.

                        • #105989

                            Another way to adjust the scope is to keep your firing position, and then adjust the turrets to bring the cross hairs onto your bullet strike.

                          • #105990

                              Very good stuff! Thanks to all! :good:

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