How To Adjust Sights/Scope (Without Wasting Ammo)
April 1, 2014 at 5:04 pm #105979Brian from GeorgiaParticipant
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.
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
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
April 1, 2014 at 5:29 pm #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.
April 1, 2014 at 6:34 pm #105981
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
April 1, 2014 at 9:18 pm #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.
April 1, 2014 at 10:11 pm #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.
April 2, 2014 at 9:08 am #105984JohnyMacParticipant
Great article Brian!
“F”, do we have a “sticky” section for articles like Brian’s?
April 2, 2014 at 10:22 am #105985
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”
April 2, 2014 at 10:46 am #105986JohnyMacParticipant
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.
April 23, 2014 at 11:20 am #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!
June 21, 2017 at 12:44 pm #105988Brian from GeorgiaParticipant
Bumping an old thread – since there’s been recent talk on long range shooting.
June 21, 2017 at 3:21 pm #105989SeanTKeymaster
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.
June 22, 2017 at 4:04 pm #105990BrushpopperParticipant
Very good stuff! Thanks to all!
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