What The Hell Is MOA…
And how does it apply to shooting and your AR15?
Well it’s kind of important, of course you don’t really need to know it. But you will waste a lot of ammo just trying to get your AR15 zeroed. So before we get to zeroing our AR15 we need to take a few and dive into Minute Of Angle (MOA) and in the process beef up on your math skills and your understanding of how your Iron Sights work.
This may look like a lot at first glance, but it really is not. Don’t let the numbers intimidate you. The point here is to show you that while your math may be very precise, your IRON SIGHTS may not be. So pick up a pencil and a calculator and discover how much rounding and “close enough” are involved. It really is easy, I promise!
Don’t worry; I’ll give you some easy tables to help in simplifying this bit of wizardry.
So what is a Minute of Angle (MOA)?
Simply put it’s a unit of measure. Specifically, it’s an angular unit of measure (talking circles here), 1/60th of 1 degree. Another way to say it is that there are 60 minutes in one degree and we are looking at one minute in that degree, 1/60th, a pretty small number.
Officially 1 MOA = 1.047” at 100 yards
Unofficially 1 MOA = 1” 100 yards
Good news is we don’t care about the official number. Here is why, at 1000 yards the size of our circle is only 0.47” larger than if we just round our MOA to 1” at 100 yards.
Here are some fancy visuals to help.
Official MOA
Unofficial MOA
4 MOA (The AR15 is no worse than a 4 MOA rifle)
Can you see how little the difference there is? I hope so because you will begin to see a trend throughout the rest of this article. Now lets get into how this effects us when zeroing our AR15.
To start off we will go over the most common zero distances, the Army 25m, the Marine 36y and the 50 yards. We will go over the how and why each click equals what it does at distances closer than 100 yards.
To start we need the base MOA values of the AR15/M16 A2/A2/M4 (16”)/M4 (14.5”):
If your AR is patterned after a M16A2, meaning it has a 20” barrel and a fixed carry handle (8/3 rear elevation drum), the sight adjustments values are as follows:
Front Sight: ~1.25 MOA (meaning each click will move the impact of the bullet roughly 1.25” up or down at 100 yards)
Windage Knob: ~0.5 MOA (meaning each click will move the impact of the bullet roughly 0.5” left or right at 100 yards)
Elevation Drum: ~1 MOA (meaning each click will move the impact of the bullet roughly 1” at 100 yards)
Why are these approximate? This is due to the differences in the actual front sight post measurements, sight radius etc. The MOA adjustments can get very complicated if you try and be too exact. Remember, these are IRON sights, not optics. Think of all these values as “Close Enough”.
If your AR15 is patterned after an M16A4, meaning it has a 20” barrel and a flat top upper receiver with a detachable carry handle (6/3 rear elevation drum) then the sight adjustments values are as follows:
Front sight: ~1.25 MOA
Windage Knob: ~0.5 MOA
Elevation Drum: ~0.5 MOA*
*Do you see the difference in MOA between the A2 8/3 drum and A4 6/3 drum? This is due to the difference in thread pitch of the rear sight base.
If your AR15 is patterned after an M4, meaning it has a 16” barrel* and a detachable carry handle (6/3 rear elevation drum) then the sight adjustments values are as follows:
Front Sight: ~1.875 MOA
Windage Knob: ~0.75 MOA
Elevation Drum: ~0.75 MOA
* The military M4 has a 14.5” barrel and you as a civilian cannot. Well you can but that’s a different discussion. Before you get into NFA (National Firearms Act) items and Short Barreled Rifles (SBR’s) as short as legally allowed is a 16” barrel, or a 14.5” barrel with a pinned flash suppressor equaling 16”. Also understand that the M4 is also referencing the notches cut into the barrel, “M4 cuts” which serve the purpose to attach an M203 grenade launcher to it.
*Another point of clarification here, I am lumping the M4 (16”) and all 16” “Mid Length” gas systems into this category. It may not be exact, but the point here is to also show you, that none of this is actually all that exact anyways.
For a 14.5” AR15 (M4 style- SBR or Pinned Flash Suppressor) with a detachable carry handle (6/3 rear elevation drum) the sight adjustment values are as follows:
Front Sight: ~1.75 MOA
Windage Knob: ~0.75 MOA
Elevation Drum: ~0.75 MOA
So these are the values we’ll use.
You will see the math for Exact numbers and “Close Enough” numbers. The reason for this is to help you see how little the difference actually is.
Army 25m Zero
A2/A4 25m Zero Target
M4 25m Zero Target
These targets can be found here.
Exact math:
To start with the Army Target at 25m
To get the values for each click at 25m
25m = 27y
100y/27y = 3.7 (This is our constant for 25m)
Close Enough Math:
25m is close enough to 25y
100/25 = 4 (this is our “close enough” constant)
Elevation Exact
A2/A4
1.25 MOA = 1.25” at 100y
1.25”/3.7 = 0.337” per click at 25m
Close Enough
A2/A4
1.25 MOA = 1.25” at 100y
1.25”/4 = 0.31” per click at 25m
Exact
M4 (16”)
1.875 MOA = 1.875” at 100y
1.875”/3.7 = 0.50” per click at 25m
Close Enough
M4 (16”)
1.875 MOA = 1.875” at 100y
1.875”/4 = 0.46” per click at 25m
Exact
M4 (14.5″)
1.75 MOA = 1.75″ at 100y
1.75”/3.7 = 0.47” per click at 25m
Close Enough
M4 (14.5”)
1.75 MOA = 1.75” at 100y
1.75/4 = 0.43” per click at 25m
Windage Exact
A2/A4
0.5 MOA = 0.5” at 100y
0.5”/3.7 = 0.13” per click at 25m
Close Enough
A2/A4
0.5 MOA = 0.5” at 100y
0.5”/4 = 0.125” per click at 25m
Exact
M4 (16”/14.5”)
0.75 MOA = 0.75” at 100y
0.75”/3.7 = 0.20” per click at 25m
Close Enough
M4 (16”/14.5”)
0.75 MOA = 0.75” at 100y
0.75/4 = 0.18” per click at 25m
Exact MOA at 25m
Close Enough MOA at 25m
Time to apply
Note- When numbers fall between 2, error on the lower click value (usually). Fire a 3 shot group and adjust again if needed.
Elevation
If we are 2” low at 25m?
Exact
A2/A4
2″/0.337 = 5.9 = 5-6 clicks (Matches A2/A4 Zero target)
Close Enough
A2/A4
2”/0.31 = 6.4 = 6 clicks
Exacts
M4 (16”)
2”/0.5 = 4 clicks (Matches the M4 Zero target)
Close Enough
M4 (16”)
2”/0.46 = 4.3 = 4 clicks
Exact
M4 (14.5”)
2”/0.47 = 4.25 = 4 clicks (Matches M4 Zero target)
Close Enough
M4 (14.5”)
2”/0.43 = 4.6 = 4-5 clicks
Windage
If we are 1.5” right at 25m?
Exact
A2/A4
1.5”/0.13 = 11.5 = 11-12 clicks (Matches A2/A4 Zero target)
Close Enough
A2/A4
1.5”/0.125 = 12 clicks
Exact
M4 (16”/14.5”)
1.5”/0.20 = 7.5 = 7-8 clicks (Matches M4 Zero target)
Close Enough
1.5”/0.18 = 8.3 = 8-9 clicks
A2/A4
M4
Do you want a 3rd way?
You can always take the distance from our “POI center” from the POA center and multiply that by either our Exact constant or “Close Enough” constant for our given distant to extrapolate what our POI center would be at 100 yards and use our true MOA values. Confusing? Lets break it down in numbers to make this easier.
Elevation Exact
2” at 27y = 2”x3.7 = 7.4” at 100 yards
A2/A4
7.4”/1.25 = 5.92 = 5-6 clicks
M4 (16”)
7.4”/1.875 = 3.9 = 4 clicks
M4 (14.5”)
7.4”/1.75 = 4.22 = 4-5 clicks
Close Enough
2” at 25m = 2”x4 = 8” at 100 yards
A2/A4
8”/1.25 = 6.4 = 6 clicks
M4 (16”)
8”/1.875 = 4.2 = 4-5 clicks
M4 (14.5”)
8”/1.75 = 4.5 = 4-5 clicks
Windage Exact
1.5” at 27y = 1.5”x3.7 = 5.55” at 100 yards
A2/A4
5.55”/0.5 = 11.1 = 11-12 clicks
M4 (16”/14.5”)
5.55”/0.75 = 7.4 = 7-8 clicks
Close Enough
1.5” at 25m = 1.5”x4 = 6” at 100 yards
A2/A4
6”/0.5 = 12 clicks
M4 (16”/14.5”)
6”/0.75 = 8 clicks
A2/A4
M4
Here is a work sheet provided to me by Roger Lomshek which may help you with this 3rd method.
See if you can get the same numbers?
Marine 36y Zero Target
You can see how this target rounds all the elevation adjustments.
This target can be found here.
Exact
100y/36y = 2.7 (this is our constant)
Close Enough
36 is close enough to 1/3rd of 100 which is close enough to 3 (this is our “Close Enough” constant).
Elevation Exact
A2/A4
1.25 MOA = 1.25” at 100y
1.25”/2.7 = 0.46” per click at 36y
Close Enough
A2/A4
1.25 MOA = 1.25” at 100y
1.25”/3 = 0.41” per click at 36y
Exact
M4 (16”)
1.875 MOA = 1.875” at 100y
1.875”/ 2.7 = 0.69” per click at 36y
Close Enough
M4 (16”)
1.875 MOA = 1.875” at 100y
1.875”/3 = 0.62” per click at 36y
Exact
M4 (14.5″)
1.75 MOA = 1.75″ at 100y
1.75”/2.7 = 0.64” per click at 36y
Close Enough
M4 (14.5”)
1.75 MOA = 1.75” at 100y
1.75/3 = 0.58” per click at 36y
Windage Exact
A2/A4
0.5 MOA = 0.5” at 100y
0.5”/2.7 = 0.18” per click at 36y
Close Enough
A2/A4
0.5 MOA = 0.5” at 100y
0.5”/3 = 0.16” per click at 36y
Exact
M4 (16”/14.5”)
0.75 MOA = 0.75” at 100y
0.75”/2.7 = 0.27” per click at 36y
Close Enough
M4 (16”/14.5”)
0.75 MOA = 0.75” at 100y
0.75″/3 = 0.25” per click at 36y
Exact MOA at 36y
Close Enough MOA at 36y
Time to apply
Elevation
If we are 3.5” low at 36y
Exact
A2/A4
3.5”/0.46 = 7.6 = 7-8 clicks (36y Zero targets claims 7 clicks for the A2/A4/M4, claiming 0.5” per click at 36y)
Close Enough
3.5”/0.41 = 8.5 = 8-9 clicks
Exact
M4 (16”)
3.5”/0.69 = 5 clicks
Close Enough
M4 (16”)
3.5”/0.62 = 5.6 = 5-6 clicks
Exact
M4 (14.5”)
3.5”/0.64 = 5.4 = 5-6 clicks
Close Enough
M4 (14.5”)
3.5”/0.58 = 6 clicks
Windage
If we are 1.5” left at 36y?
Exact
A2/A4
1.5”/0.18 = 8.3 = 8-9 clicks (36y Zero target claims 9 clicks for the A2/A4 claiming 0.5” per every 3 clicks, 3 clicks = 0.5”)
Close Enough
A2/A4
1.5”/0.16 = 9.3 = 9-10 clicks
Exact
M4 (16”/14.5”)
1.5”/0.27 = 5.5 = 5-6 clicks (36y Zero target claims 6 clicks for the M4 claiming 0.75” per every 3 clicks, 3 clicks = 0.75”)
Close Enough
M4 (16”/14.5”)
1.5”/0.25 = 6 clicks
Ready to try the 3rd way again? What was it again?
You can always take the distance from our “POI center” from the POA center and multiply that by either our Exact constant or “Close Enough” constant for our given distant to extrapolate what our POI center would be at 100 yards and use our true MOA values. Confusing? Lets break it down in number to make this easier.
Elevation Exact
3.5” at 36y = 3.5”x2.7 = 9.45” at 100 yards
A2/A4
9.45”/1.25 = 7.56 = 7-8 clicks
M4 (16”)
9.45”/1.875 = 5 clicks
M4 (14.5”)
9.45”/1.75 = 5.4 = 5-6 clicks
Close Enough
3.5” at 36y = 3.5”x3 = 10.5” at 100 yards
A2/A4
10.5”/1.25 = 8.4 = 8-9 clicks
M4 (16”)
10.5”/1.875 = 5.6 = 5-6 clicks
M4 (14.5”)
10.5”/1.75 = 6 clicks
Windage Exact
1.5” at 36y = 1.5”x2.7 = 4.05” at 100 yards
A2/A4
4.05”/0.5 = 8.1 = 8-9 clicks
M4(16”/14.5”)
4.05”/0.75 = 5.4 = 5-6 clicks
Close Enough
1.5” at 36y = 1.5”x3 = 4.5” at 100 yards
A2/A4
4.5”/0.5 = 9 clicks
M4 (16”/14.5”)
4.5”/0.75 = 6 clicks
50 yards BullsEye
Target can be found here.
Enough with targets that give you number. What about a generic bullseye at 50 yards?
Lets get our constant, this one is easy. We are working only in yards and in whole numbers.
Exact
100y/50y = 2 (this is our constant)
Close Enough
Ha, don’t need it this time! It’s all exact!
Elevation Exact
A2/A4
1.25 MOA = 1.25” at 100y
1.25”/2 = 0.625” per click at 50y
Exact
M4 (16”)
1.875 MOA = 1.875” at 100y
1.875”/2 = 0.93” per click at 50y
Exact
M4 (14.5″)
1.75 MOA = 1.75″ at 100y
1.75”/2 = 0.875” per click at 50y
Windage Exact
A2/A4
0.5 MOA = 0.5” at 100y
0.5”/2 = 0.25” per click at 50y
Exact
M4 (16”/14.5”)
0.75 MOA = 0.75” at 100y
0.75”/2 = 0.375” per click at 50y
MOA at 50y
Time to apply
Elevation
If we are 0.75” low at 50 yards?
Exact
A2/A4
0.75”/0.625 = 1.2 = 1 click
Exact
M4 (16”)
0.75”/0.93 = 0.8 = 1 click
Exact
M4 (14.5”)
0.75”/0.875 = 0.85 = 1 click
Windage
If we are 2.25” right at 50 yards?
Exact
A2/A4
2.25”/0.25 = 9 clicks
Exact
M4 (16”/14.5”)
2.25”/0.375 = 6 clicks
What about the 3rd way here?
You can always take the distance from our POI from the POA center and multiply that by either our Exact constant or “Close Enough” constant for our given distant to extrapolate what our POI center would be at 100 yards and use our true MOA values. Confusing? Lets break it down in number to make this easier.
So this is simple right?
Elevation
0.75” at 50y = 0.75″x2 = 1.5” at 100 yards
A2/A4
1.5”/1.25 = 1.2 = 1 click
M4 (16”)
1.5”/1.875 = 0.8 = 1 click
M4 (14.5”)
1.5”/1.75 = 0.85 = 1 click
Windage
2.25” at 50y = 2.25”x2 = 4.5” at 100 yards
A2/A4
4.5”/0.5 = 9 clicks
M4 (16”/14.5”)
4.5”/0.75 = 6 clicks
Now in the end understand that all the above is merely a place to start for a basic understanding. If you really want to get your MOA for your specific rifle here is how you do it.
Pick a distance that you can shoot tight enough groups to reduce shooter error.
- Fire a 3 shot group
- Give the sight (do each sight separate) 10 clicks in adjustment
- Fire another group.
- Find the POI center of each group and measure that distance.
- Divide that measurement in inches by 10 (the amount of clicks you chose)
- Divide that number by the MOA value at that distance you shot at.
MOA at:
25 = 0.25”
50 = 0.5”
100 = 1”
If you shot at 50 yards and your distance between groups is 5″ for 10 clicks in adjustment then our math looks like this:
5″/10 clicks = 0.5″ per click
Since we know 1 MOA at 50y = 0.5″, we divide 0.5″ (change per click) by 0.5” (1 MOA at 50y) and get the MOA value per click of your rifle.
0.5”/0.5 = 1 MOA per click.
Another example
At 25 yards your POI center to POI center measures 3” on 5 clicks in adjustment.
3”/5 = 0.6 per click
MOA at 25y = 0.25”
0.6”/0.25 = 2.4 MOA per click
Since math is all about repetition here is one more.
At 25 yards your POI center to POI center measures 4” on 10 clicks in adjustment.
4”/10 = 0.4 per click
MOA at 25y = 0.25
0.4”/0.25 = 1.6 MOA per click.
That’s it!!!
After all that math, you did all that math right? Here are some easy tables for you.
Exact Elevation/Windage
Close Enough Elevation/Windage
Some extra worksheets provided by Roger Lomshek
I would also like to thank Roger, he is a Appleseed instructor and my backstop as I bounced my numbers etc off of him. Also provided the math on acquiring your exact MOA value. Much appreciated!
*This post and the information herein is for informational and educational purposes only. Use at your own risk. Always follow the 5 rules of Firearms Safety when handling any firearm.
*If you like this content and would like to support the page you can do so here.
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