Bindon aiming concept training
(U.S. Marine Corps photo by Cpl. Thomas J. Griffith)
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It’s the Marine Corps’ fault. They were the ones who got this whole mess confused. It might not be doctrinal Marine Corps training, but it is the training taught by NCOs to junior troops. Even Primary Marksmanship Instructors teach it.

The Bindon Aiming Concept (BAC) is easily the most misunderstood firearms concept out there currently, and it’s largely because the USMC teaches Marines the wrong thing. I know because they taught me and if you look hard enough into the early days of my writing about guns, I’ve likely described it in the wrong way myself. So forgive me, but consider this to be my attempt at redemption, if you will. 

What The Bindon Aiming Concept Is

The BAC is a shooting technique designed to allow you to track a moving target in the field. It’s a technique that requires an illuminated reticle. With both eyes opened you track the target by focusing with your off eye while keeping the reticle on or close to the target. 

The ACOG can do both Occluded shooting, and the BAC (Courtesy Trijicon)

Once it comes time to shoot your target, you switch focus to your dominant eye through the optic. Now you have the precise magnified view and can exercise proper shot placement. It’s simple, effective, and very useful. 

While it’s not hard, learning to rapidly change focus between your eyes on target at different distances might be a bit jarring at first. The more you do it, the faster and more comfortable it will become. 

What the Bindon Aiming Concept Isn’t

I (and many Marines) was taught that the Bindon Aiming Concept (BAC) was a two-eyes-open shooting method used with magnified optics for close quarter’s shooting. The USMC issued ACOGs, and largely still do and this fixed 4-power optic is an amazing combat rifle optic. 

You see, we were taught that at close range the Bindon Aiming Concept was keeping both eyes open while shooting. The bright red reticle would be superimposed over the target and we could accurately engage targets without the optic’s magnification getting in the way at anywhere from 1 to 25 yards. 

Illuminated reticles are required for both occluded and BAC shooting (Travis Pike for TTAG)

This is not the Bindon Aiming Concept. This is something of a non-occluded occluded shooting method. Occluded shooting was a very early concept in which a rifle ‘optic’ was not a device you could see through. Instead the optic’s objective cap is on and the shooter used both eyes open to superimpose the illuminated red dot in the center of the shooter’s vision. 

You can see through an ACOG so technically that’s not occluded shooting, but the method remains the same and remains effective. Although some prefer to cover the front lens, I’ve never found this necessary as long as I can focus with my off eye. It’s the same method you’d use with a mud-covered red dot optic. 

Both Eyes opened is a requirement for both shooting styles (Travis Pike for TTAG)

The confusion about the system is due to a number of reasons. First, the BAC is defined as a two-eyes-open shooting concept. Second. Glyn Bindon was the sole importer of the Armson OEG occluded red dot optic. He’s tied to both and he pushed both the BAC and occluded shooting methods. Third, you can use both an occluded shooting technique and the BAC with the Marine’s beloved ACOG. 

Confusing Times 

Both the occluded shooting technique and BAC have a lot in common, but they are distinctly different. Most people likely use them instinctively without ever knowing which is which, or even what they are called. I hope this clears up some of the non-existent confusion many may have had. 


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  1. Lol, I initially parsed this as “The Biden aiming concept,” and was thinking, “What? Fire a couple shotgun blasts through the door?”

    • If it makes you feel better, you weren’t the only one with that passing through the first thought.

    • I also first read that as “Biden”. Though to be fair I saw the picture, with that Marine’s atrocious chicken wing, before I read the title of the article. Which meant it made even more sense for it to be a reference to the “Biden Concept”

      • Chicken wing. Then i though Popeyes Chicken sounds good right now.

        But for shooting with both eyes open, for handguns, and close up targets only, for the past few years i’ve been using the CAR stance with great success.

  2. When you qualify as expert at 500yds with open iron sights , you don’t need no stinkin ACOG…word…!

    • So, what is considered USMC ‘Expert’ at 500 Y?

      Lead on a 10-inch target?

      • In my day (early 80s) we had to hit a silhouette target at 500 yards firing our rattle-trap, beat-to-shit Vietnam-era M16A1s. We were expected to hit a 12” paper target at 200 and 300 yards.

        • The thing with AR15 type rifles is because the sights are on the same side of the hinge pin, any play in receivers doesn’t matter if is doesn’t affect the function.

          Try using a FAL type rifle with some sloppy fit between the receivers and you will have a tall/thin group. At 300m the vertical string of the group would be 4x plus the width.

        • It was the same for me in 1995, except it was a beat to shit rattle trap A2 that never left CONUS.

    • I qualified expert with both the iron sights from my A2 and later with a ACOG on a M4. Only difference was I dropped a total of 8 points for the whole week with the ACOG. While yes you need to know how to use and should be good with irons first, don’t disregard optics that can make you that much better and faster.

  3. Nope. Didnt clear up anything for me. In fact it caused even more confusion since there was no instruction, much less recognition of, the third eye.

  4. Never even heard of BAC. I don’t on an ACOG and only one rifle that would readily accept one. It has a Leupold extended eye relief Scout Scope on it. I shoot with both eyes open. Scored many great shots. First was a running whitetail at about 75 yards. Heart shot. Sold. Last was three wild hogs with three shots before they could get out of the field. Awhat?

  5. New fangled lazer dot battery scopes… it’s just not right! Kids these days getting everything handed to them by their smart cellular telephones. Now get off my lawn!

    • Nate, it’s the video games. They will cause the fall of Western Civilization as we know it.

      • Those video game have generated strong interest in real guns for the kids that play them. I’m not gonna dump on first-person shooter games or unrealistic ‘John Wick’ movies, since they motivate who watches them to get real guns…

        • The problem is it drove up prices too! As soon as I came into a little bit of money Garand rifles were over a thousand dollars a piece and the SKS qent from 100 bucks in 200 to 600 or more these days. It sucks!!

    • The ACOG uses a fiber optic element to capture sunlight and luminate the BAC reticle within the sight. USMC doesn’t want to have to rely upon batteries for their primary stock weapons. It’s a whole other story when it comes to NVG compatible systems. The AN/PVS-14 NVGs, AN/PEQ-15, and other ATPIAL aiming devices all have to take batteries, but they’re working on a reduction of those consumable resources (i.e. lithium batteries) in the “near” future.

  6. Never knew there was any other way to shoot than with both eyes open. 1 on target and 1 on surrounding area. Taught this way by my father over 50 years ago. Made many running shots on critters from rabbit/squirrel to deer/hogs. Using rifles and shotguns. All without the need for an optic. learning to hunt for survival teaches a person what really matters.

  7. These methods go out the window when you have a weak left eye like I do.
    My brain TOTALLY IGNORES the left input unless I totally close my right eye.

    I discovered this little phenomena during a driving eye test and they put two different images in the two different eyepieces and the only thing I saw was the right image. After being asked 4 times as to what I was seeing I then closed my good right eye and then all of a sudden the image from my fuzzy left eye was now seen by my brain. Cool. Also explains why I suck in eye/hand coordination.

    If you think about it I guess that’s actually a pretty good feature of the brain. Why distort your total perceived image if the one eye is underperforming. Better just to see a clear mono image than a goofed up stereo image. I however don’t understand how the brain knows that the one eye is poor and to ignore that one.

    Maybe some optomologist here will tell me that Im full of crap.

    • There is one here who is an eye surgeon, so hopefully he’ll chime in…

    • I would say definitely not full of crap…I am in the exact same situation, left eye and everything! Have been all of my life, never knew until a doctor pointed it out once.
      I hate that anyone else has to deal with it, but it’s kinda reassuring to know at least SOMEONE out there understands what it’s like. Most people just look at me funny when I try to explain it.
      I guess when you’ve seen the world a certain way all your life, it’s hard to imagine it any other way.

      • It’s a condition called lack of stereopsis. I have it too. You also can’t see the 3D in a stereoscope (like a View Master). And I have to blink my eyes left-and-right to read those images in the driver’s eye test at the Secretary of State office. I had an ophthalmologist tell me that, if you don’t have it by the age of seven, you aren’t going to get it. Damn! I’m waaaay past seven now!


        “Occluded shooting was a very early concept in which a rifle ‘optic’ was not a device you could see through. Instead the optic’s objective cap is on and the shooter used both eyes open to superimpose the illuminated red dot in the center of the shooter’s vision.”

        You also can’t do THAT with a lack of stereopsis. Finally, people who DO have stereopsis can be pretty arrogant about it too.

        • Thanks for the term of stereopsis

          Did some reading and it seems like the brain is doing what they call Binocular rivalry.
          Also the condition is termed stereo blindness.

    • Not strange at all to those of us who wear contact lenses. If one lens should fall out, I retain clarity AND distance so long as both eyes are open. The brain is a wondrous tool, indeed.
      Even in cases of normal vision, two images are combined into a single composite. The DMV has a different idea, though.

  8. When I aim a telescope with a magnified finder I always keep both eyes open. I’ve learned to superimpose the crosshair on the other eye’s view. Very useful aiming trick, at least MY brain likes it. This doesn’t seem to translate to firearms though. Maybe because telescopes make less noise.

    • You would be hard pressed to find a rifle of equal quality for the same kind of money as the “poverty pony”.

  9. Whut? All’s I know is that I can “zero” my ACOG to get hits at +/- 2″ from point of aim, from 50′ to 100yds and there is no battery. It costs a lot of money but is worth every penny.

  10. For those of us who didn’t know (including yours truly), ACOG stands for “Advanced Combat Optical Gunsight” according to Acronym Attic.

  11. So, i has been shooting deer this ways for sometime and didnts no it. I’s must bees a jeanius. Mys grandady mus uv taughts me rite.

  12. I was taught (when I was a kid, taught by my grandfather) from Day One to shoot with both eyes open all the time and I’ve never seen any sighting arrangement yet that requires an eye to be closed.

    Serious question here…. do most people not keep two eyes open when shooting??? It seems to me that closing an eye while shooting, especially if near other people and not in a controlled range type environment, is begging to eventually follow in the footsteps of Dick Cheney.

    • My dad and sister are both left eye dominant, but right handed, and so this is how they shoot as well.

  13. I’m glad so many of you are so advanced.
    I close my eye that is not looking thru the sights.
    As a lefty shooter, that is my right eye.
    With a magnified image, it is difficult to see the magpies in one eye and non magnified in the other.
    It is a million times easier to just close the right eye and concentrate on keeping the crosshairs centered.
    With a red dot, it is indeed possible to keep both eyes open.
    I find I am far more accurate if I close the one eye.

  14. The Bindon Aiming Technique requires an illuminated reticle for many people but not all. The key is to have enough contrast with the reticle that you can still see it when tracking with your non-dominant eye. I’ve seen guys who can do it with old Redfield wire crosshair scopes; although I’m not one pf them.

  15. Just run drills through a shoot house with an ACOG and you’ll figure things out pretty quickly.

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