How to Shoot with a Reflex Sight (Red Dot)

When the Army adopted reflex optics, many units were slow to use them. Aimpoints sat on shelves in arms rooms while soldiers trained with iron sights. After all, the joes might break them! And anyway, the Sergeant Major never shot with optics when he was a young soldier, so neither will his soldiers.

Then we went to war.

Suddenly, many soldiers found themselves with an unfamiliar piece of equipment sitting on top of their rifles and carbines. NCOs had to quickly train their soldiers on their proper use. Problem was, many NCOs had never been trained. I began to overhear some really weird stuff as NCOs struggled help their troops.

“You gotta make a lollipop”

“What does CCO stand for, sergeant?”
“It means close combat optic. That’s why it isn’t accurate over 100 meters.”

“The dot replaces the rear sight. Put the dot on the front sight post, put the front sight post on the target, and squeeze the trigger. That’s called co-witness shooting.”

WHAT?! Other NCOs and I spent a lot of time trying to teach soldiers the proper use of Aimpoints and EOTechs and trying to combat improper training. Now I find that most civilians who ask about purchasing a reflex sight are also asking about their proper use.

Reflex sights work well because aiming is simple.
Forget lollypops and 100 meters. Co-witness has nothing to do with proper sight picture. The secret to the reflex optic is this: if you can see a red dot, and the red dot is on your target, the bullet will hit the target. No aligning sights. No sharp front sight and blurry target. No critical cheek weld. Here is how it’s done:

With the weapon on safe at the ready, identify and focus on a target. Keeping both eyes open, bring the weapon up to the firing position. As the sight comes up in front of the eyes, a red dot will appear in front of the eyes. When the red dot reaches the point of aim, switch to fire and engage the target. Both eyes remain open and the focus never moves from the target.

Aiming becomes a quick reflexive action.

Always keep the reticle brightness adjusted as low as possible for lighting conditions. This will give a clearer sight picture and obscure the target less. A common complaint I hear about red dot optics goes like this, “On sunny days in Arizona, I have to turn the brightness almost all the way up in order to see the reticle.”  Well, Duh. That’s what that knob is there for, so use it. Turn it low in the dark, and high in the sunlight or snow. If you are using night vision, you will need an optic that has lower intensity settings for night vision use. Otherwise, if using a monocular (ANPVS-14, etc.), put the monocular on the non-firing eye and make sure it is aligned well (no double image when looking at a distant light, for example). Then use the naked eye for the optic, and the two images will be super-imposed.

How to Zero
Zeroing a red dot sight is the same as zeroing any rifle scope, with the additional process of zeroing back-up iron sights if you have them. I prefer to boresight  before I go to the range. Once you have your boresighted weapon on the range, either remove the optic if necessary, or sighting through it, zero the iron sights. While zeroing the iron sights, leave the optic turned off and ignore it. Once iron sights are zeroed, flip them down, if possible. Turn the optic on and zero according the the manufacturer’s instructions. While zeroing the reflex sight completely ignore the iron sights, other than to use them to index the optic if you are not bore sighting.  They are two different sighting systems and have nothing to do with each other. The iron sights are not zeroed to the dot, and the dot  is not zeroed to the iron sights.

If both your iron sights and your red dot sight are zeroed well, don’t worry about where they are in relation to each other. I have observed great frustration on the range when soldiers tried to get the red dot to line up on top of the front sight post and still have the weapon shoot to point of aim. I had an M68 (Aimpoint) on an M4 that, when zeroed, positioned the dot above and to the right of the front sight tower. Both iron sights and the Aimpoint hit dead on.

But they are only accurate for short range shooting, right?
I hear this repeated over and over again by soldiers, on forums, and in magazines. The Government nomenclature for the Aimpoint sight was the M68 CCO. Many instantly assumed the acronym stood for Close Combat Optic. Maybe the word close was just easier to spell than collimating. Whatever the reason, this designation caught on and led to the often repeated myth that reflex sights loose all accuracy when used for targets over 100 meters away. If a sighting system is accurate at 50 meters, why would it not be accurate at 250 meters? It should still be as accurate at 800 meters, but at extended ranges we begin to get into the issue of effectiveness. The sight won’t loose accuracy at long ranges, but at a certain point, depending on skill and eyesight of the shooter, magnification may increase effectiveness. Effective is not the same as accurate.

The original designation for the M68 was Collimating Combat Optic. This simply meant that the sight collimates a projected reticle (aligns the light so that the beam does not spread) and reflects it off a mirror that is designed to reflect one specific colour of light. Thus, while the reticle is reflected back toward the eye, the image from the front of the sight is allowed to pass through with no magnification. This puts a reticle on the same focal plane as the target, allowing the eye to focus on both the target and reticle simultaneously. Parallax is almost eliminated in quality sights. The result is that close targets can be instantly targeted and hit, no matter where the head is in relation to the weapon. If the dot is visible, placing it on the target will result in a hit. At longer ranges, cheek weld (position of the cheek against the stock) becomes more critical. Minor parallax can cause insignificant deviations in point of impact at close ranges, but at long ranges this error is magnified. The solution is to pay more attention to eye position, as you do when shooting with iron sights or a standard rifle scope.

How do I get my reflex sight to co-witness?
Much discussion revolves around how to get particular reflex sights, back-up iron sights, and mounts to all work together to co-witness. Part of the problem is that most people seem to feel that that it is absolutely necessary that the iron sight picture to correspond exactly to the red dot reticle. In other words, when the two systems are viewed together, the red dot is in the exact point of aim of the iron sights. Many people even recommend using the two together. My idea of the ideal use of back-up iron sights is simply the ability to use the iron sights through the optic, should the optic become inoperable. I prefer the iron sights low in the reflex sight picture if the front sight does not flip down, so that the sight picture is obstructed as little as possible. What you do not want to see is a red dot centered squarely somewhere on the back of a front sight tower – the dot must be above the front sight or the target will be obscured. I see no reason to spend a bunch of money trying to shim things around to get a dot perfectly lined up with iron sights I hope not to use anyway. The purpose for co-witnessing is to use one sighting system to verify the zero of the other. If this is important to you, than do it. Otherwise don’t worry about it. If the two systems are set up to co-witness, and one day they don’t line up, which one moved? You still have to go to the range to figure it out. Remember that, depending on the shooter and the sight, even if everything is set up correctly, the two systems may not seem to line up exactly when both are zeroed.

What type of reflex optic should I buy?
This depends on the type of firearm, the type of shooting you will do, and the price you are willing to pay. Whether or not you will be shooting with night vision can also be a determining factor. The main thing to remember is that you get what you pay for, and this is especially true for optics. Optics are expensive to build, and low price usually requires low quality.

I have more experience with Aimpoint optics than any other reflex sight systems. I like Aimpoints a lot and have had trouble with only one (an issue sight that someone had damaged). All others have worked very well. They are easy to use and can withstand a lot of abuse. The only problem I have had is that I often bumped the power switch and activated the sight. I learned to check it often to avoid draining the batteries when it was not in use. Newer Aimpoints have much longer battery life.

My favorite reflex optic is the Mepro M21. It is ideal for very fast CQB type shooting. It also allows more radical shooting positions than some other types of sights. The Mepro M21 is available with several types of reticles for different purposes and preferences, including dot, bullseye, open X, and triangle. The best thing about the Mepro M21 is that it requires no batteries. There are no electronics or switches – the sight is always on. Using ambient light through a fiber optic collector system, the reticle automatically  adjusts to ambient light. When you go from a dark room to a desert street, the reticle becomes brighter. When you enter another dark building, the reticle dims appropriately. In total darkness, the reticle is illuminated by tritium and the sight is night vision compatible. The Mepro M21 is built like a tank, and due to a design that does away with electronics, batteries, and has no delicate internal moving parts, it is the ideal combat optic. It is impervious to water, sand, cold, etc. It can be mounted on your weapon with the well-designed quick-detach mount, zeroed, and basically forgotten – you simply know that any time you pick up your weapon the sight is on and good to go. It is the standard issue sight for the Israeli Defense Forces.

The EOTech sights are similar to the Mepro M21 sights in how they work and look. The difference is that EOTechs require batteries and have to be turned on and off, and the brightness must be adjusted. There have been some issues with some sights losing power under recoil, but the issues have been addressed by EOTech, and overall, they are good sights.



For pistols, or for piggyback use with a higher magnification optic, there are small reflex optics available from several companies, including Docter Optic, JP Enterprises, Inc., Trijicon, Burris, Sight Mark, and others. The Trijicon RMR sight is the only one that the manufacturer says can get wet, and I have seen them banged around quite hard, so it would be my choice for any heavy use.

There are quite a few nice looking reflex optics out there that we have not had the opportunity to test, but as we do, we will let you know what we think of them. If you have a comment on an optic you have used, we would be interested to hear it.

All content ©7.62 Precision.  Contact 7.62 Precision for permission to use material from this site.  Comments are welcome.

43 Responses to “How to Shoot with a Reflex Sight (Red Dot)”

  1. I read an article that made great sense.
    It recommended Zeroing the red dot not in its center, but on its Top edge. That way, since the dot doesn’t actually grow nor move, you can always precisely place the dot’s edge on your point-of-aim, no matter how large the dot apears, and how much of the target it covers !


    • This is not a bad idea. I zero sights with triangle reticles to the point of the triangle. However, if the dot is too bright and appears larger, that will shift the point of impact slightly. In most situations in which red dot sights are used, this won’t make any practical difference, though.


  2. I have an AR15 and SW MP15 .22 – with both I use (red dot) reflex without iron sights. As stated they are not needed. With the .22 I hit 100m (unsupported) half inch groups and 200M 1.5in groups – and I am hardly a good shooter. I think it is easier to shoot with a red dot than iron sights at 50m or more with a much faster target acquisition, better eye focus, better target view and more field of view (situational awareness). No small wonder that iron sights are relegated to being a “analog” back up.


  3. Thanks for all the information; it is “news I can use”. I am (now) a civilian shooter who first learned in the military. This technology is new to me so I am researching its suitability before I run out and buy one. I will say this about “lollipops” and aligning with iron sights: it is good to have the confidence that if the electronic sight fails, though that isn’t likely, that the iron sights can be immediately put to use. To me, this particular instruction, whether necessary or not, is about confidence in the weapon.

    Liked by 1 person

  4. I prefer the Aim point Patrol Optic sighted in at 50 yards. I didn’t intend to necessarily co-witness the Aim point with my iron sights, but that’s the way the bore sighting worked out for me. The Optic also has settings for night vision gear. I believe there are 7 settings in all. Great advice on using low light on the Optic setting! I learned the hard way.


  5. I prefer the Aim point Patrol Optic sighted in at 50 yards. I didn’t intend to necessarily co-workers the Aim point with my iron sights, but that’s the way the bore sighting worked out for me.


  6. I really like how things were explained in great detail!! Thanx for your time and patience…. Also what’s your opinion on firefield optics or rex optics have purchased 1 of each have boresighted at 50yrds but haven’t thrown any metal through my American tactical55.6/.223 or my gsg. 522.. Do you have any suggestions or exp to pass along


  7. I got a vortex sparc II today and sighted it in at about 30 yards and it was dead on but when I started shooting at about 60-75 yards it was shooting about 6″ high how is that happening?


    • This is happening because your sight is above the bore. If you think about it, your line of sight through the sight is straight toward the target, and the bullet is leaving the bore an inch and a half or two inches or so below the center of your optic. In order for your bullet to arrive at the same location you are aligning your sight with at 30 meters, the rifle has to be zeroed so that in 30 meters your bullet rises from the level of your bore to the level of your sight. Past 30 meters it continues to rise above your line of sight, and you will begin to hit high, until the upward rise of the bullet is overcome by gravity and the bullet begins to drop. At some point downrange the bullet will again intersect the line of sight, and then drop below, and you will start to hit low. So your line of sight is a straight, horizontal line. The trajectory of your bullet is a curved line, starting under your line of sight, crossing it at your close zero range, then arching above your line of sight before dropping back through it at your far zero range. So this is something that needs to be considered when deciding on a zero range, and the zero range is generally adjusted to the intended use of the rifle.


  8. Some of your information is correct while other pieces are completely false…. IF you were EVER an Army NCO you sure didn’t bother to read FM 3-22.9 starting on page 8-12 for CCO which DOES stand for Close Combat Optic.y

    Below paragraph 8-23 is the note:
    “NOTE: The aiming method used to zero MUST ALSO BE USED TO ENGAGE TARGETS.”

    Paragraph 8-29, sub paragraph 3 says: “Adjust windage and elevation on the reflex sight until the CENTER OF THE AIMING DOT IS AT THE TIP OF THE FRONT SIGHTPOST when viewed through the BUIS while assuming a normal firing position.”
    The “lollipop” was some GOOD NCO’s attempt at making an easy to understand analogy for Soldiers to understand. But in defference to them I always taught the “Snow Cone” analogy because you should only vave half of the red dot above the apex of the front sight post.

    In addition the “parallax issue” exists below 50 meters NOT 100 meters… AND the CCO IS accurate past 100 meters, but ONLY if used in conjunction with the front sight post and the Zero aimpoint is approximatley 1.4 cm (1.5 on some zero targets) below target center mass … again failure to follow this step will make the CCO inaccurate past 100 meters

    I love cleaning up the miss information of FOBbits who sat in the safe confines of a FOB and never actually engaged the enemy.

    As I See NOTHING but praise here; I can only assume that you will delete this reponse soon but hopefully some will see the CORRECT information and where to find it BEFORE you delete my input.


    • Several points here:
      Don’t assume you know me or what my experience is. I have nothing to prove to you, but it is foolish to make assumptions about people you do not know. There are a lot of people in this industry who know me and calling me a Fobbit does nothing to improve their perception of you.

      1. You are confusing zero techniques with shooting techniques. When you zero an optic, the best technique is to first get the optic as close to zeroed as possible. This can be done by bore sighting using one of several methods. It can also be done by indexing one sighting system to another. In other words, if your iron sights are already zeroed, then, looking through the iron sights at a target, adjust your reticle so the dot rests on the top of the front sight post. This does not zero your sight, it prepares your sight to be zeroed. It gets you close enough that your first group should be on paper and you can adjust from there. But once you index the optic to the iron sights, you ignore the iron sights and zero the optic using only the reticle. I admit that the manual could be better written to avoid confusion, but after indexing the two systems, zeroing and shooting with the optic are correctly done without involving the iron sights.

      One of the weaknesses of the Army is that soldiers are often taught steps and not concepts. They are given the steps to perform a task, but not taught the concept between each step. This was the case with the M68, and the result is NCOs who were mistaken in the correct use because they did not understand the concepts behind it.

      2. “The aiming method used to zero must also be used to engage targets.” That simply means to use the same positions an techniques when fighting as you did when you zeroed. When you correctly shoot to zero, you don’t use you iron sights. When you PREPARE to zero, you use your iron sights to index the sight’s reticle if you are not using a boresight kit. Again, you, like many other well-meaning NCOs, are confusing the foresight step with the shooting steps of zeroing.

      3. I never gave a range at which parallax becomes apparent, or if I did it was a typo. I certainly would never claim that it appears out to 100m. It is different in different sights – many cheap sights exhibit parallax at any range, but most quality sights will exhibit parallax only from zero out to maybe 10m or 15m; ranges at which the parallax has no practical effect on effectiveness of the sight. So when you see a video review of a red dot sight, and the reviewer aims the sight at a wall 5 feet away and moves the camera around behind the sight to show that there is parallax, it is an unfair review – parallax should be checked at 50m, not 5 feet.

      4. The idea that a red dot sight is accurate over 100m only if used in conjunction with the front iron sight shows a lack of understanding about how optics work. If the sight is accurate at 100 meters, it is just as accurate at 200 meters, and just as accurate at 600 meters. The only factors from the sight itself that can effect accuracy at extended ranges are:
      A. The size of the reticle. At longer ranges the size of the dot will show an apparent increase compared to the size of the target. So a dot that was the size of a button on the target’s shirt at close range is the size of his head at a further range. This decreases the shooter’s ability to refine his point of aim. One trick to reduce this issue is to adjust the reticle brightness down until the target can be seen through the reticle.
      B. At ranges at which holdovers are necessary, not every shooter is skilled in estimating precise holdovers.
      C. On some sights zero adjustments are coarse, so while appropriate for a 150m or 250m zero, may not give a precise zero at 600m. This is not detrimental to the intended use of a non-magnified sight.

      Around the time this article was written, CCO was stated in the manuals to stand for Collimating Combat Optic. In use, soldiers called it a close combat optic, and this soon began to show in print, so at this point, I would say that either nomenclature is correct.


  9. This is excellent. Thank you so much for explaining the parallax issue and chin placement. I was sighting in my High Point 995 with a Sight Mark reflex sight at 50 yards. I was getting really good tight hits on target. My uncle tried shooting and he was all over the place and complained about no front sight (I had completely removed it from the 995). I’ve been searching for why he had so much trouble and until I found your article, no one could verify what I suspected. My military training taught me to always lock my chin in the exact same location on the stock. This became habbit. My uncle was never taught this and accustom to fixed sights on rifles. He would never put his chin in the exact same place on the stock, and thus his hits were all over the place at 50 yards. As you mention, the accuracy is magnified by distance to target. While I had little trouble at 50 yards, he flatly couldn’t use the reflex sight.


    • Likely with the cheaper sight, parallax is experienced, which you overcame using your correct shooting techniques, just as you would with a scope or iron sights. On the higher-end reflex sights, parallax is reduced and eye placement is less critical.


  10. I guess my questions didn’t post. I’m super new to these sights, not sure what i should see in terms of the front post just looks so much different than my peep sights.


    • When shooting with the red dot sight, just ignore the front sight post. Since your focus will be on the target you will kind of see the front sight tower, but it won’t really be something you notice.


  11. Back to shooting after a decade, only ever shot iron sights and peep. Got a not expensive red dot, and the same for reflex to mount. In both cases my weld and sight picture seem super high. Not sure how far to set relief (do these use relief?) Not sure if it’s because they are designed like that, these were cheaper or what. With iron sights i have a normal stock weld, with the other two it’s almost like its my jaw welding, and the picture is still high. Any video or pic of what i should be seeing? Just don’t feel like dropping $300 if I’m going to end up using the iron or peeps anyway. It’s also my wifes first plinker, so i need easiest i can get.


    • Your head will often be slightly higher than with iron sights, but not always. Your stance will help with head position, too. You want your head up looking at the target, and the rifle brought up to your cheek, not your head brought down to the rifle. Place the stock as high as needed on as close to the center of your chest as possible.

      The cheaper reflex sights will tend to give you a poorer experience than the a quality sight, and if you get a quality sight, with the right mount, it should work very well. You can go with a sight/mount combination that gives an absolute co-witness, which will put the reticle at the same height as your iron sights, or you can use a combination that gives you a lower-third co-witness, which puts the reticle above your iron sights, so that your sight picture is less cluttered.

      Keep in mind that if it is a quality sight with reduced parallax, the reticle will kind of follow your eye, so wherever you put your head, if you can still see the reticle, you can still hit the target.

      You don’t have to buy the most expensive sights. My favorite sight is the M21 (click here to see the M21), but the Mepro RDS (click here to see the RDS) is a very good military-quality sight for an excellent price, the Aimpoint Pro is very affordable, and if you go down a bit in price, the Vortex Strikefire has a reputation for solid quality and the price is very reasonable. I wouldn’t go any lower in price than the Vortex, or you start to see very noticeable decreases in quality.


      • Great article! What do you think of the different reticles available on the M21? I probably will do a 1/3 co-witness on my rifle and typically zero my irons at 100. Any idea how big the triangle is? I am leaning towards it (the triangle). I am thinking just zero the M21 at the top point of the triangle at 100…Very well written and informative. Thanks again.


        • I like the triangle. The tip gives a precise aiming point, and the whole triangle makes a very fast, large dot for close-in work. I also like the Open X.


      • With the mount that comes with the M21T, is it set up as a 1/3 co-witness with a flat top? I have a Daniel Defense M4V1 flat top with the fixed sights. Will this optic work with that setup to your knowledge?


  12. Excellent article, Thank You! Looking forward to reading more.


  13. Wow, what a well put together article.
    You helped me decide what I want to do with my new optic. I have a Bushnell red dot mounted on my ultimak railed gas tube for my ak…
    Since the ultimak is so low my red dot is cowitnessed.
    I think I’m going to zero my Bushnell in
    So that point of impact is about 5-6 inches above my point of aim at 100yards.

    I feel that type of zero will allow me to be precise at any reasonable range of engagement. And if not, or if my optic shuts out on me (I live in az, **** gets hot) I still have those ak iron sights to rely on. All in all, jolly good show.



  14. Well done and many thanks.


  15. so tell me what’s the benefits of using head up display (open) reflex sight configurations as compared to using tube, scope like config? I have no idea which one is better


    • You are asking about the benefits between an Aimpoint and EOTech configuration, not between a reflex sight and magnified optic I am assuming?

      There is a more in-depth article that I wrote on this subject here:

      Short answer is that despite a lot of hype and internet arguments, if the sight is used correctly, with both eyes open and focused on the target, in use they are pretty much the same. People argue about field of view and the tube limiting field of view, etc. but a lot of that comes from marketing hype, applying logic brought over from magnified scopes, and using the sights improperly with one eye closed.


  16. Excellent article. Thank you.


  17. This is the best article on the subject I have ever seen. Answered all my questions. Thank you very much.


  18. please use 50 yds zero at top of the red dot … have app.250 yds zero all within battle zone zero ….


  19. This has changed my whole pereption of what a reflex sight is, what it is for, and what it is capable of. Especial love the low light applications versus iron sights and lighted retical scopes.

    Thanks for taking the time to put this together and for doing it so well.


  20. […] you will understand not only the purpose for, but also the proper use of, reflex/red dot sights. […]


  21. I gained a lot of knowledge about this new technology from this article. I am rigging up a system for my shotgun for turkey hunting and this makes a lot of sense to me since I want a wide field of vision.
    Thank you,


  22. Thank you for the clarification! You must be a NCO backbone of the Army, Hooah!


  23. Thanks for this info. Great, easy to understand article. Found this while trying to figure out how to zero my new sight. Like your other information and your work looks incredible. Keep up the writing.


  24. Thank-you


  25. Great info! Thanks a bunch.


  26. Excellent information! Really helped me understand how to properly implement my new red dot sight! Thank you!


  27. Thanks for the great tip about adjusting the brightness.
    The brightness of the dot was obscuring the target, duh.


  28. Thanks for the great article! I found this article while doing a search to understand why there would be any significance to co-witnessing since the dot and the front sight post don’t line up with the red dot on POI. I was thinking that ideally, I wouldn’t even be able to see the front sight through the optic, but it’s a fixed sight. It seems the guys at the gun store counters may not have ever used the sight, as I was told if everything is correct, the red dot should be an absolute co-witness sitting right on top of the front sight post. I thought I had a problem since my red dot is high and to the right.


  29. great information. i as well just found this article. thanks for great info..


  30. Agree, just found it and it answered many questions I have had. Thanks for the article!


  31. Im not sure how old this article is but I just wanted to say that I thought it was a great piece!! Thanks!


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