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Help me understand co-witnessing.

Discussion in 'Rifle Discussion' started by ThatOneGuy1231, Nov 10, 2010.

  1. ThatOneGuy1231

    ThatOneGuy1231 The great northwest Member

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    So I set up my AR with with a free standing rear sight and I put an aimpoint 512 on it. Currently my red dot is in perfect alignment with my irons. Having them all in line doesn't really bother me.

    But I was reading that a good co-witness should place your irons in the lower 1/3 of the sight picture.

    But I don't understand how you would have the same POI with your irons lined up below your dot.

    Also, for a red dot does the dot have to be lined up in the center to be on target? or is it paralax free and anywhere you see the dot is on target?

    Sorry for all the newb questions, but I've grown up with scopes and irons, and this hole red dot is new to me.
     
  2. MrNiceGuy

    MrNiceGuy between springfield and shelbyville Well-Known Member

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    the aimpoint should be parallax free.

    Once you have your iron sights aimed in, every time you aim down the iron sights, the red dot should sitting just on top of of your front iron sight.

    I dont know who you heard that from, but it's horribly wrong. POI is POI.
    If you are aiming down your iron sights, the red dot should agree, otherwise one or both are horribly misaligned.

     
  3. ThatOneGuy1231

    ThatOneGuy1231 The great northwest Member

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  4. MrNiceGuy

    MrNiceGuy between springfield and shelbyville Well-Known Member

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  5. Skang

    Skang WA Well-Known Member

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    Aimpoint is not 100% parallax free. (very close range)

    Far as reliable goes, Aimpoint > Eotech.

    never sigh-in iron sight and red-dot/optic together.

    you should always sigh-in iron sight 1st, and red dot.
     
  6. DoubleTapDrew

    DoubleTapDrew Oregon Well-Known Member

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    I think the lower 1/3 cowitness is probably for folks who have fixed front sights so it's not interfering with the red dot. My flip ups cowitness with my eotech and I won't be seeing them unless the red dot goes down.
     
  7. Riot

    Riot Benton County, Washington Well-Known Member

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    Where did you get that idea? An EOTECH screen can have a bullet hole in it and still maintain a zero by moving the recticle in a different area of the screen.

    (EOTECH VIDEO)

    This is true...if you sight in your iron sights, all you have to do is slap on the red dot and "battlesight zero it" to your iron sights. You can do this by simply looking down your sights while adjusting the red dot, then moving the red do to your front sight post.

    Saves a lot of time on the range and bullets...
     
  8. wsu 5.9er

    wsu 5.9er Spanaway WA Member

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    Until the battery dies because you left it on too long, or the recoil from shooting turns it off. ;)

    EOTechs are not horrible, but an Aimpoint is much more reliable. :thumbup:
     
  9. Riot

    Riot Benton County, Washington Well-Known Member

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    The low battery indicator blinks on and off when battery life is low (and only for the initial 5 seconds)...and will only do it with recoil when battery is very low (user manual). You can actually check the battery life in an EOTECH by turning the unit off then back on...if it blinks on and off for 5 seconds, battery life is below 20%. The Aimpoint just dies when the battery does and has no battery life indicator.


    FYI, I actually prefer the Aimpoint over the EOTECH. I think the EOTECH is too expensive and takes up too much sight picture with the huge recticle...the Aimpoint is just a dot (and has a lot more adjustments in brightness to light conditions and preferences than the EOTECH). However, I will refrain from putting my personal biasness and state that one is better than the other because, in fact, that is not true. They both have their pros and cons and I'm sure many people can tell you that they like one over the other and vise versa.
     
  10. wsu 5.9er

    wsu 5.9er Spanaway WA Member

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    Having owned both, I can tell you the Aimpoint is much more reliable than the EOTech. I went through three sets of batteries in the 1.5 years I owned an EOTech. I'm still on the same set of batteries for my Aimpoints.

    Military/LEO users have had many problems with EOTechs, from them turning off by themselves to completely failing in combat. L3 is aware of the problem regarding the battery springs and issued a "kit" to attempt to fix the problem. It did not work 100% and they still have issues. Even the new XPS sights are failing under moderate to hard use.
     
  11. Riot

    Riot Benton County, Washington Well-Known Member

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    Now THAT I did not know...good info (I knew that the Aimpoint battery lasts like 10X longer, but the rest I had no idea. I never had a problem when they fielded the EOTECHs in our unit, but we only had them for about a year and I brought my own ACOG anyways).
     
  12. ThatOneGuy1231

    ThatOneGuy1231 The great northwest Member

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    On a red dot note... when a red dot is zero'd in. is the dot always on target? or is it only on target if centered in the eyepiece?
     
  13. Riot

    Riot Benton County, Washington Well-Known Member

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    Only holographic sights are zeroed in regardless of the angle you look at it from.
     
  14. itgoesboom

    itgoesboom Hillsboro Member

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    True, but with an Aimpoint the parallax is minimal, under 1" IIRC at less than 50 yards, and 0" beyond 50 yards. Between the two, I'll take an Aimpoint due to battery life, reliability and durability. :thumbup: If Aimpoint had a reticle like EOtech, L3 would be out of business. If Eotech had Aimpoint's reliability and even 1/10th the battery life, Aimpoint would be out of business.

    What constantly blows me away about the optic debate is how you can hear about so many people who have EOtechs, even the newer XPS/EXPS series who have serious issues develop with the optic, and than you will hear from others who have put EOtechs through **** with no issue whatsoever. It's either the greatest thing in the world, or it's the worst.

    As for the original question dealing with co-witness, there is a good video on youtube currently that deals with it.

    YouTube - Optic Mount Height Discussion - Absolute Cowitness vs. Lower 1/3 Cowitness
     
  15. stitchclimber

    stitchclimber St. Louis Active Member

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    For either an aimpoint or an eotech the dot is on target no matter where the dot appears.
     
  16. MrNiceGuy

    MrNiceGuy between springfield and shelbyville Well-Known Member

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    That's funny, I was just about to say the same thing about aimpoints.
    You either hear that they're indestructible, or that they're a POS.

    It must be a selective attention grabber, because I keep reading stories like this:
    The only real advantage I see the aimpoint having is the battery life.
    Personally, I really prefer the larger and brighter reticle of the eotech, and 64 days of continuous battery life is plenty for me. If battery life was my main concern, I'd get a Trijicon Reflex site.
     
  17. RallySoob

    RallySoob Salem, OR Active Member

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    The reason they are saying it is 'better' is because you normaly dont shoot with both irons and eotech on. So with just the EOTech on you have increased your target accuisiont speed when using the riser. And you still have the ability to co-witness your sights when needed...

    lower 1/3 co-witness; they are referring to the co-witenss effect scope risers like the larue 110 eotech risers have. It makes for faster target accusition because the scope is raised a bit thus requiring less time to setup a solid cheek weld thus allowing you to aquire a target faster. Since the POI is the same between your raised eotech and your iron sights the eotech sight will be co witnessed just as it would be without the riser but the eotech ring will be at the lower portion of the screen when co-witness. I've ran that setup before and I did not like it so I sold the EOTech riser and just ran my eotech as far forward on the upper reciever as possible.

    Aimpoints are not more reliable than EOTechs. Dont buy that bs... EOTech is the better sight. It offers the fastest target accuisition available today and is 100% parralex free which alone makes it superior imo. LE/M have been using them for years w/o fail! They have had known issues w/ battery life come up with 'certain models' but have revised them from my understanding. They have had a bad batch or 2 but when mass producing complex electrnoics like that I think its reasonable. Aimpoints are NOT 1MOA good luck hitting small targets at 100yds plus...
     
  18. Martini_Up

    Martini_Up NW USA Well-Known Member

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    So in your own experience it is only about battery life. having owned both you didn't find that the target acquisition was much quicker with the eotech? or that your accuracy out to 300 meters was spot on with the eotech? you chose the aimpoint because the batteries lasted longer?? :bluelaugh:
     
  19. wsu 5.9er

    wsu 5.9er Spanaway WA Member

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    I like the EOTech reticle better but I was just as accurate with the Aimpoint out to 200 meters, even though it has a 3 MOA dot. I was actually faster with the Aimpoint too. After owning the EOTech and having my own issues with batteries, I heard about all the issues EOTech/L3 has with batteries/sights failing/etc. Enough evidence for me to get rid of it.

    If you like the EOTech and it works for you, great. I had one and I had problems with it. I read about many others having problems with it and I got rid of it. Couldn't be happier with my Aimpoints. :thumbup:
     
  20. RallySoob

    RallySoob Salem, OR Active Member

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    The fact you say you are faster with the aimpoint than the EOTech leads me to believe you will say whatever you have to in order to convince yourself aimpoint is better. And its costing you target accusition speed ;)

    And your field of view is cut down with a tube style RDS.

    The HWS is better in the rain too... no matter how wet the screen gets the reticles is bright and easy to see. 2 eyes open aiming as you should be and you won't even notice if mud were on the screen

    HWS FTW!