When you are buying red dot sight, you come accross the term of MOA. What does it mean? Very simply, MOA means the size of the dot. In other words, 1 MOA red dot will be much smaller than 3 MOA red dot.
MOA red dot: practical view
Ok so MOA means the size of the dot. What are the implications of it? Well if you have smaller dot (smaller MOA) then you will be able to shoot more precisely – the dot will be very small and cover very small area on the target.
The dot size remains the same but as the target is further and further from you, the dot covers larger and larger part of the target.
Lets say if you have 2 MOA dot:
- if the target is 100 yards from you, the dot will be 2 inches large,
- if the target is 50 yards from you, the dot will be 1 inch large,
- if the target is 200 yards from you, the dot will be 4 inches large.
Therefore you will like more larger MOA for shorter distances and smaller MOA dots for shooting at larger distances.
Red dot MOA: technical explanation
MOA stands for minutes of angular measurement. How does it relate? If you have any circle, the circle is 360 degrees. And if you devide one degree by 60, then you have 1 minute of angle = 1 MOA.
Why is it used for red dots? Because one minute of angle tells us the difference in distance.
Lets say you aim two pointers from the same spot, but you aim them very slightly different way. Lets say you aim them 1 minute of angle different from each other.
Even though the pointers are located at the same spot, the dots from the pointers will be furter and further away as we will move the target. And if the target is 100 yards away from the pointers, the difference between the two dots will be 1 inch. And for 200 yards it will be 2 inches, for 300 yards 3 inches and so on.
The minute of angle (MOA) tells us how large the dot will be on the target. The red dot MOA as such stays the same, but with longer distances the dot covers larger and larger area.
Make sure to see our article on explanation of MRAD in optics. Must read when selecting optics.
Use of MOA in red dot sights
As we have the idea behind MOA explained, we can move to the idea why red dots use it. The reason is simple – the measurement of MOA tells us how large the dot will look on a target based on the distance of the target from us.
- If we shoot on a target 100 yards away with 3 MOA dot size, it will appear as if the dot is 3 inches large on the target.
- And if we shoot on a target 100 yards away with 6 MOA dot, it will appear as if the dot is 6 inches large on the target.
That leads us to the final idea of the MOa: for larger distances we want to use smaller MOA, for shorter ranges we want to use larger MOA. And why is that?
Because with larger MOA for close range we dont have to be dealing with the negative of too large appearance of the dot on the target – because the target will be close to us and the dot will still look small. And on the other side, we get the positive of larger MOA of easy and fast aiming. Because the larger the dot, the easier it is for you to aim.
And vice versa – for larger distances we want to use red dot sight with smaller number of MOA. In that case the idea is following – with small dot (small MOA value) we the dot will not cover so much area in the distance. Thus 1 MOA in 100 yards will be only covering 1 inch of area. Thus we will be able to aim much more precisely. The negative then be that the aiming process will take longer.
Which MOA is the best
With red dot there is no such thing as universal best. It all depends on the purpose of use.
For your pistol you will most probably be good with 3 MOA dot size or 4 MOA dot size. But it could be even as large as 6 MOA red dot for home defense gun.
For your red dot sight on a rifle you will probably go for smaller MOA dot. The smaller MOA dot will be much more precise for longer ranges.
Red dot sights or iron sights?
I heard this story so many times – first you refuse the red dot, then you try it, then you do not want to shoot without red dot again.
It is simply easier, more precise to use red dot for aiming compared to iron sights. Also target acquisition (aiming proces) is consdierably faster with red dot. With standard sights you have to align 3 points to aim properly. With red dot sight it is only one – the red dot.
On the negative side, optic sights are much larger and the compactness of a gun is hurt by use of the optic device. And despite the usual very long battery life, the red dot still needs source of energy to function.