I just opened my box to play with my new EOTech 552.A65 Rev-E

The first thing I did was put the batteries in it and lay in on my workbench approx 12” from my eye and looked through it, just to see the unique sight picture…

The EOTech website Spec's page says quote “Transmission holography - 100% parallax free”, but I noticed that when I move my head around the reticle also moves around.  To make sure I was not imagining this, I put a thumbtack in the wall and aimed the EOTech at the thumbtack and sure enough if I move my head to the side, the dot moves off the thumbtack.

Is this not parallax?  I was under the assumption no parallax means that no matter where my eye is in relation to the sight the dot should stay on the target and not move off, is this wrong???

Granted I know this little experiment is not a real true to life situation like when the EOTech is mounted on a rifle; on the bench my head has a much greater degree of freedom than it does on the rifle with anything close to a cheek weld.

This parallax may be insignificant & negligible when the sight is in use, but is it not in fact parallax?  Am I missing something in this experiment which tainting my results?

I’m excited to try it on my rifle, and I’m not discouraged by this little experiment as I have had EOTech sights recommended by a great many knowledgeable people, I’m just curious to know if others have found similar characteristics?

Also, I remember reading a post here by someone who did a parallax test, and in fact found some then notified EOTech and was asked by them to send their sight back for inspection, has there been any word about that yet?

[url]http://groups.msn.com/TheMarylandAR15ShootersSite/carbine2day1.msnw[/url]



[url]http://groups.msn.com/TheMarylandAR15ShootersSite/carbine2equipmentreview.msnw[/url]

If one of the members could do a search of the archives I posted a few months back about this issue.

It was the never ending thread on Aimpoint vs EO Tech.

I did read that 8 page battle or whatever it was, but I wanted to try and keep this just EOTech and not another X vs. Y battle

I was really just wondering if I was doing my little test/experiment wrong, and if others have had similar experiences.

Well I just pulled my 552E off my rifle and did the same test ... pair of nails in the wall across the room with the Eotech sitting on a solid base.  At the very edges of the view I was getting what appeared to be 1-2 dot widths of movement (as measured by the nails).  I've never really noticed this before while shooting.  The closer I was to the optic the farther I had to move my head to get this effect.  My EOtech is sitting just in front of my ARMS 40, and I use a nose to charging handle cheek weld so I'm pretty close to it when I'm shooting.

Now I'm finding myself wanting an Aimpoint so I can compare them further. :)

Do you mean this one?

[url]http://www.ar15.com/forums/topic.html?b=3&f=18&t=164971&w=searchPop[/url]

Well I believe I figured out what I was missing in the EOTech parallax dilemma…
 
When I was doing my little experiment my thumbtack on the wall was too close, probably like 10 feet (3 to 4 yards).

When you get a sight picture on a target with iron sights; your eye, rear peep, front sight post, and the target are all lined up.  If the rifle were to remain perfectly still, like in a vise or on a rest, and you move your head the front sight post will no longer be lined up with the target because the line of sight from your eye to the target has changed.  Well in my previous experiment at close range like 10 to 12 feet the thumbtack on the wall was basically acting like a front sight with a really long sight radius.

Doing my same little experiment last night in my backyard at 25 & 50 yards I had no noticeable effect of the reticle moving off target as the reticle moved around due to my head moving around…

Now any error that may exist, will only exists at extreme close range, will be extremely small and potentially negligible.

I did a little test this morning moving my head to move the reticle from the extreme left to extreme right of the window and documented the approx reticle movement at the given ranges to try and calculate the potential error.

( Yards / Reticle Movement / POA-POI Error )
3 / 1 complete 65MOA Reticle / Potentially 2” Error
6 / ¼ of the complete 65MOA Reticle / Potentially 1” Error
9 / 3 complete 1moa dots / Potentially 0.3” Error
12 / 1 complete 1moa dot / Potentially 0.1” Error

Regardless of the potential error documented above, who is going to be aiming at 3 yards to the goblin anyway? 1” error at 6 yards is still within an eye socket and the potential error at 9 yards is basically equivalent to bullet hole through bullet hole precision…

Somehow the holographic reticle knows where your eye is and moves the reticle to show you the POI. (A phenomenon of the light passing through the crystal to your eye???)

So I’m now positive that as I move my head the reticle does move, but it is in fact not parallax.  Now to prove my hypothesis about potential error, and how negligible it is, I’m going shooting this Friday and will test this phenomenon for myself at various ranges 7, 10, 15, 25, 50, & 100 yards.

I’ll post my findings ASAP.

Excellent work Omega!

I d be real interested in your finding as well, since I have an EOtech.

Great job Omega_556!  I was just discussing this issue with SMGLee, I'll be looking foward to reading your test results.

KW951 noted the closer you eye was from the sight the more you had to move your head did you notice the same thing?  When you run your tests maybe you could also vary your eye relief to see if it make a difference.

[b]Quoted:
When you run your tests maybe you could also vary your eye relief to see if it make a difference.[/b]

Will do, but I don't have a forestock rail system yet so I don't have a whole lot of adjustment.

I can remove my ARMS#40 and mount it to the back of the receiver, collapse my stock and put my nose right to the charge handle for short eye relief; and I can mount it as far forward as I can on my receiver and extend my stock all the way out and keep my head back near my shoulder for long eye relief; but that is the max of the adjustment I can create.

I’ll measure the actual eye relief distances and include them in the results.

The only real test is one where you go out and SHOOT the darn thing.

Now go back re-read the thread (at least my posts in the thread) and you'll see the experiment I did.

I actually fired (!!) the rifle at a target 50 yards away.  With the same point of aim (Center of the target) I would fire with the reticule in various positions in the screen (extream left & right edge, upper & lower corners, etc..)

I found at 50 yards with the reticule all the way to one side the bullets were hitting several inches to the other side of the point of aim.  (that is right INCHES).

Lumpy has a scan of the target - if he wants to post it that is ok with me.


Live fire experiments have show the error exists out to 50 yards (I haven't been out to the range to test it at other distances).  While the error is meaningless for a COM shot - I would be concerned if trying a head shot.

[b]Quoted:
The only real test is one where you go out and SHOOT the darn thing.

Now go back re-read the thread (at least my posts in the thread) and you'll see the experiment I did.

I actually fired (!!) the rifle at a target 50 yards away. With the same point of aim (Center of the target) I would fire with the reticule in various positions in the screen (extream left & right edge, upper & lower corners, etc..)

I found at 50 yards with the reticule all the way to one side the bullets were hitting several inches to the other side of the point of aim. (that is right INCHES).[/b]

Forgive me for not bowing at the alter of Forest, [hail2]
Forgive me for having questions and trying to learn as much as I can before I have a chance to go to the rifle range and shoot it this Friday.

[b]In the first post of this thread I wrote:
I remember reading a post here by someone who did a parallax test, and in fact found some then notified EOTech and was asked by them to send their sight back for inspection, has there been any word about that yet?[/b]

Now I know that was you; your post was the one that made me question this in the first place.

Instead of jumping my ass and discounting my findings you could have just acknowledged that it was you, and you haven’t heard anything from EOTech yet; that could have been constructive.

[b]Posted by Forest:
BTW I've been contacted by EO Tech - it seems they are concerned about my unit's parallax issue (it shouldn't have one) so they are sending me a new unit and asking for mine back for testing. When I get a chance to test the new unit out I will report back.[/b]

Now until I hear the feedback from EOTech from your experience this tells me absolutely nothing. This is a statistical population of [b]1[/b] and no conclusion can be drawn from that.  Do all EOTech units have parallax? Was yours defective? Did you blunder your testing procedure and get inaccurate results? Who the hell knows until more information is gathered… I must be in error for not listening to you, the great forest, and trying to gather more data on my own and posting my findings as I find them.

[b]In my third post of this thread I wrote:
Now to prove my hypothesis about potential error, and how negligible it is, I’m going shooting this Friday and will test this phenomenon for myself at various ranges 7, 10, 15, 25, 50, & 100 yards.

I’ll post my findings ASAP.[/b]

Forest, I apologize I don’t live on a rifle range with the ability to receive a new product, check it out, install it, and test it in the same day. I just got it yesterday, for Christ’s sake, and I’m going to the rifle range Friday to test it out, I apologize for any inconvenience I may have caused you. [rolleyes]

I also apologize for being a mechanical engineer, and being very curious about how this technology works, and posting what I am doing while trying to figure it out…

On a side note Forest, www.MD-AR15.com is a great site. I built one of your toolbox projects and I love it…

i have them both and i prefer the aimpoint. As for the eotech its am aimpoint on welfare but its perfect for the mossberg due to accuracy is not much of an issue
shotgun eotech
ar15 aimpoint
ar10 acog

I got an aimpoint ,older pre cet, and found it had parralax at close distance. I heard they don't become completely free of parralax until about 75 yards. My eotech appears to be the same way. It has never been an issue and have shot some pretty impressive groups at 175yrds with the eotech. The aimpoint covers to much to shoot nice groups at that distance for me.

[b]Quoted:
i have them both and i prefer the aimpoint. As for the eotech its am aimpoint on welfare but its perfect for the mossberg due to accuracy is not much of an issue[/b]

I was hoping we could just keep this thread on topic of EOTech parallax issues, not yet another Aimpoint vs. EOTech thread, I guess this just isn’t possible.

Would you care to elaborate? Your post is useless for anyone looking for factual information, it is anecdotal & subjective at best???

What type of accuracy have you found your EOTech capable of, and at what distance(s)?

Please explain why you feel the EOTech is an Aimpoint on welfare?

Why type of shooting are you doing that you need a dot sight on a shotgun, is it a slug gun?

[b]Quoted:
I got an aimpoint ,older pre cet, and found it had parralax at close distance. I heard they don't become completely free of parralax until about 75 yards. My eotech appears to be the same way. It has never been an issue and have shot some pretty impressive groups at 175yrds with the eotech. The aimpoint covers to much to shoot nice groups at that distance for me.[/b]

Very interesting, I had never heard that the Aimpoints had any parallax issues. Is there anything in the CET technology that would eliminate this problem, or does it still exist in the later units.

How much error have you found in your EOTech due to parallax between POA & POI, and at what ranges under 75 yards?

While nothing in this life is 100% the EOtech is damn good ,if you use the EOtech long enough you don't notice any of the flaws .I have 2 (1)551 and (1) 552 I can't seem to miss with ether (long or sort) up to 150 yds .all else aside I bought mine for the fast sight acqusition and at that they are unequaled .They are a great sight for those who can get used to the minor flaws .they are a lot like women I don't think there is a perfect one .

Save the Bowing and worship for The Lord.

However if you're passing the plate please send $$ and 5.56 ammo to PO Box 343..... [;)]

Maybe I overdid it - or perhaps you missed the point.  Either way let me rephrase it.

Having people say 'nice job on the work' is fine - but I'd rather people look at what I did and say "I wonder if [i]mine[/i] is that way" and repeat the experiment and post the results.

If more people repeated the test we would have a larger database to draw some conclusions.  With this database we could determine if my results were anecdotal or if there really was a problem with the system.

Shooting at distance is the only way to tell if there is a problem.  Up close (within a few meters) most any optic will have some parallax, but holding the sight and guestimating the error has its own flaws (you may move the rifle/sight and not realize it).  Shooting a group eliminates judgement errors and you have a physical record of how far it was off.

I'll post the procedure he so others don't have to wade through the thread and figure it out:

1) Zero the rifle with the reticule centered (or near enough to it).  I recommend zeroing at 50 yards - though I'd be interested in seeing this test repeated at 25y & 100y (after trying it at 50y).

2) We're going to move the reticule around the outside of the screen in a clockwise manner while firing groups of 2 or 3.  For this test you will ignore the circle and focus just on the dot (since it is the primary aiming point).

a) Put the dot on the edge of the screen at the 12:00 position - aim at the center of the target and fire a group.  Using your spotting scope check the target and mark down where the group landed in relation to the center.

b) move the dot to the upper right hand corner and fire a group at the center of the target.  Again use the spotting scope to check and see where the rounds landed

c) repeat the above procedure for 3:00, the lower two corners, 9:00 and the upper left corner.  (note there will be no shots fired at 6:00 as the front sight tower will be in the way - if you have a folding front sight then go for it!)

3) Go get the the target (the results) and compare to your notes on where the rounds landed.  You should be able to tell if the groups moved left or right - up or down (or both) based on the reticules position.

You have the results of my EO Tech 552 - I'd love to see the results from your's and the others out there.


Thank you for the kind words.  As you can tell the sight is what it is due to contributions by others (particularly from this site).  The write up for the tool box project is one of them.

I have not had the chance to do a proper test but for long range shooting, I usually have time to properly setup for the shot so I wasn't too concern with the parallex problem.  I however agree with Forest, a test is a good idea to do and have some data on paper for the public.

[b]Posted in Bold by Forest
Maybe I overdid it - or perhaps you missed the point.  Either way let me rephrase it.[/b]

It’s possible we both overdid it, I apologize for being a sarcastic ass.
I was just a little annoyed because I had/have every intention of doing a live fire test as soon as I can, and I mentioned that in previous posts; regardless we are past that now.

[b]Having people say 'nice job on the work' is fine - but I'd rather people look at what I did and say "I wonder if [i]mine[/i] is that way" and repeat the experiment and post the results.[/b]

That is exactly where I’m headed; I read your post when my EOTech was on order.  I just opened the box Monday and I’m going to shoot it Friday.

[b]If more people repeated the test we would have a larger database to draw some conclusions.  With this database we could determine if my results were anecdotal or if there really was a problem with the system.[/b]

I agree 100%

[b]Shooting at distance is the only way to tell if there is a problem.  Up close (within a few meters) most any optic will have some parallax, but holding the sight and guestimating the error has its own flaws (you may move the rifle/sight and not realize it).  Shooting a group eliminates judgement errors and you have a physical record of how far it was off.[/b]

I understand and I agree, but information can be gathered by playing with the sight on the bench.

Let me clarify the methods I used so we are all on the same page.
I placed the sight on the edge of my rollaway toolbox, and I was not in contact with the sight or the toolbox to risk moving it.
To get an idea the reticle displacement; I aimed the sight at a plum-bob and a 36” level I attached to the wall of my shop.
With approx 12” of eye relief I would move my head so that the reticle would move from the extreme left to the extreme right (same for top & bottom) and gage how much movement I perceived from the plum-bob and level.
I calculated the potential error with trigonometry; based on the angle I perceived the reticle move (1 ring = 65 moa, ½ ring = 32.5 moa, 2 dots = 2 moa) and the distance to the wall.

I apologize if it appeared that the results I posted above were fact, they were only calculations based on a hypothesis that has yet been untested showing potential error; I hope that was clear.

[b]I'll post the procedure he so others don't have to wade through the thread and figure it out:

1) Zero the rifle with the reticule centered (or near enough to it).  I recommend zeroing at 50 yards - though I'd be interested in seeing this test repeated at 25y & 100y (after trying it at 50y).

2) We're going to move the reticule around the outside of the screen in a clockwise manner while firing groups of 2 or 3.  For this test you will ignore the circle and focus just on the dot (since it is the primary aiming point).

a) Put the dot on the edge of the screen at the 12:00 position - aim at the center of the target and fire a group.  Using your spotting scope check the target and mark down where the group landed in relation to the center.

b) move the dot to the upper right hand corner and fire a group at the center of the target.  Again use the spotting scope to check and see where the rounds landed

c) repeat the above procedure for 3:00, the lower two corners, 9:00 and the upper left corner.  (note there will be no shots fired at 6:00 as the front sight tower will be in the way - if you have a folding front sight then go for it!)

3) Go get the the target (the results) and compare to your notes on where the rounds landed.  You should be able to tell if the groups moved left or right - up or down (or both) based on the reticules position.[/b]

I will follow this test procedure with minor modifications, thanks.

[list][*]I zero’d my 16” Bushmaster flattop M4gery w/ ARMS#40 sight at 50 yards and verified at 200 yards, I will do the same with the EOTech.

[*]I also want to re-check the zero of my iron sights through the EOTech window just to see if any error was induced, if so how much, and then readjust the irons for co-witnessing.

[*]I am going to shoot (8) 5 shot groups at each distance; 7, 10, 15, 25, 50, & 100 yards respectively.

[*]The 8 groups will be top(12), top-right, right(3), bottom-right, bottom(6), bottom-left, left(9), & top-left.

[*]I will fire at 6-o’clock position, even though the front sight is in the way, by shooting with both eyes open.

[*]I plan to use 5 shot groups so a flyer will be less likely to influence the results.

[*]I have 300 rounds of Federal XM193 set aside just to do this test, and zeroing (I have several cases of this stuff from ammoman.com). [/list]

I have a roll of butcher paper that I use to make my own targets.
To record the results I have made 6 targets sheets 36”x36”, each with 8 individual aiming points laid out in the position the reticle will be in while firing.  This way I can have an independent target for each range & reticle position and save the results for later analysis & critique.

I’ll post my finding ASAP

Omega: Sounds Good - Looking foward to your post!

I'm going to be headed to the range in the next week or two and I just got a couple new cases of XM193 so I'll see if I can do a test of this with my 552 as well.

I recently contacted EOTech and pointed them to this thread and invited them to join and share some info.  Here's the reply I got back.

*Please note the gentleman from EOTech who replied to me may have read this thread before all the replies previous to this one were posted.  He may also not have read the other thread regarding Forest's live fire testing.

Regardless this information from EOTech is good to know.  At the very least we have one more thing to compare to when we run our tests...

Cheers!

***

Chris,
I don't belong to the chat group. I do not know how to reply to the        group.
You can pass along the information:

What I read in the chat was someone looking across the room for parallax.
At this close distance you will notice parallax.

The sights do have parallax error of +/- 1.2 " or +/- 0.6" (1.2 " side to side). The sight is designed to be parallax free at long distance 100yds to infinity.  At close range, there will be a parallax error equaling to the width of the window which is 33mm or 1.3".  A perfectly aligned sight will have parallax error of 1.3" at 10 yds and at 17 ft.

As you move further away from 10 to 40 yards parallax becomes less and is almost zero at 50 yards.

If the sight is parallax free at 10 yds or 17 ft, it would be way out of alignment.

Best regards,
Greg Schultz, EOTech
Customer Service
3600 Green Court, Suite 400
Ann Arbor, MI 48105
Ph:(734) 741-8868
Fax (734) 741-8221
WWW.eotech-inc.com

Very interesting Yojimbo...thanks for posting the eotech reply...

[b]Info from Greg Schultz, EOTech
The sights do have parallax error of +/- 1.2 " or +/- 0.6" (1.2 " side to side).  

A perfectly aligned sight will have parallax error of 1.3" at 10 yds and at 17 ft.[/b]

Well this confirms my calculation was off.[slap]

I shoot a 511.A65 on a 16" Colt HBAR.

Never had any problems with what you folks are discussing. The post from Eotech about sums it up. No one would use a sight at the distances you were speaking of, Agreed?. Meaning the short ones.
Just my two cents worth.

???? WTF ???


Definately NOT!  Of course they would use the sights at the short distances - ESPECIALLY if you need a head shot.  Why do you think these are prized for CQB where all the shots are 'short distance'?

My Eotech is pretty much dedicated to short distances. A 100 yd shot would be rare for my Eotech (with the configuration it is in).

17-20 inches!!! You have small rooms [shock] [;)]

Sorry couldn't help it. The one I really like was [:D]

I agree though..
I'm not worried either, I've never had problems with the Eotech at close range, I just make sure the dot is somewhere near the middle of the screen.

B^)  I think I licked the wrong side of the mushroom that day.  

My test was delayed, as I had to work Friday, so I went Saturday. I didn’t have useable results, the test must be redone after Christmas.

Did it take you guys any time to get accustomed to using the EOTech, or where you up to speed right away?

The first thing I did was verifying my iron sights at 50 yards through the EOTech window, and I consistently shot a nice approx 1” to 1.5” groups.

I then fired my irons at 10 yards to see where it hit and then fired the EOTech also at 10 yards to verify I was close. (I crudely bore sighted my EOTech by over laying it onto my iron sights)  At 10 yards w/ the EOTech I had a 5 round group that looked like 3 touching ragged holes.

I then shot at 50 yards with the reticle centered just to see what type of groups I was capable of.  A few were 5 round groups that were 0.75” in diameter [:)]; others were 5 round groups of all flyers measuring 2.5” to 3” [slap]

I continued to shoot at 50 yards with similar consistently-sporadic results. No matter what I did I could keep my groups in the COM kill zone out to 300 yards, but I couldn’t hold a clean 1” (2moa) group to save my life; it wasn’t pretty.

My buddy who I was shooting with has a large gong target that we placed at 300 yards, I almost couldn’t miss it, but I couldn’t call my shots at 50 yards and tell you which ones were flyers or not.  I would think I was doing good, and it would be 3”.  I was shooting at 1” solid black circles, with a 6” cross overlaid on it.  Out of a 5 shot group I’d have one hit POA-POI right in the center of the black, then some would hit far left, far right, high, low, etc…  They weren’t consistent enough to be an incorrect zero. They weren’t strung together vertically to be a breathing problem, they weren’t sent into any consistent quadrant to be a jerking trigger either.  On Saturday I was also shooting my FAL with iron sights and had no inconsistencies at all, again shooting nice little 1” to 1.5” groups.

I think my targets were too small, as they were hard to see with iron sights, when I would focus on my front sight the 1” circles would disappear.

I, unscientifically, played with shooting with the reticle in different positions in the window and couldn’t see any difference in my screwy 5 round groups of flyers, they would still be 3” groups centered around the 1” circle…

I was very frustrated and wasn’t sure if it was the ammo I was using, my upper (it’s new and only its second time out), the EOTech, or just me sucking; so I went back to just using my irons sights through the window of the EOTech and my groups instantly went back to 1” to 1.5” consistent and POA=POI…

I open to any advice &/or public flogging you all deemed necessary, [slap]

A 17' (foot) shoot into a 2x4 target - under pressure & at speed (i.e. 1 second or under); starting from low ready?

Especially when 'cold' (no warm up shots that day).

That I'd like to see.  You must be the Yoda of the CQB combat world...

Omega sounds like you had a bad day, but it also sounds like you didn't have any parallax issues either.

If you're in the DC/MD area how would you like to come out after Christmas and run some tests with me?  I want to re-run my parallax tests at 25 & 100 yards to see what happens.

Omega, I had the same problem my first time out with the Eotech. I didn't have the sight on tight enough. You might want to recheck that. Other than that I'm at a loss.

If I tighten it hand tight and then a 1/4 turn extra, it does loosen up on me. I had to tighten it down really good.

Forest,
It was a bad day alright, a frustrating day really.
Thanks for the invite, I’d love to, but I’m in the Southwest.

Ridge,
This may have been the problem!!!
I used the large slot screw not the small cap screw.  The instructions said something to the effect of tighten with fingers until resistance is felt and then use a nickel or similar sized object and tighten another ¾ turn.  

Well I am not sure what “tighten with fingers until resistance is felt” actually meant so I tightened finger tight and then when I tried to use the nickel to turn an additional ¾ turn it was getting very, very, tight at approx 3/8 to ½ turn. I was afraid of over tightening so I stopped there; maybe it was loose after all…

Should I  see if I can borrow a small torque wrench and do the 17 in/lbs or whatever it was in the instructions, or should I just grab that f#@king nickel and turn it as tight as I can with my fingers and try again???

What procedure do you guys use to tighten the thing down, any advice appreciated?

Omega_556,

When installing the EOTech make sure to...

1. Push it forward tight against the rail.  Recoil tends to make your optics shift forward so why fight it.

2. Tighten the thumb screw hand tight as tight as you can then use a coin to give it an extra 1/4" turn.

3. Repeat your testing and let us know if your shooting becomes more consistant.

Cheers!

I did pretty much what Yojimbo said, but I think I was too delicate on the hand tight part. So my 1/4 turn didn't hack it.

Sounds to me like your's should be on pretty good. I sure don't think it will hurt to double check it and tighten it up a bit more.
All I can say is, I thought I had mine on tight the first time and then my groups started being erractic and stringing. I snugged up the nut and the problem was solved for me.

Maybe it's a matter of getting used to the reticle.

Definately looking forward to more testing. Maybe if I get a chance I'll do some of my own.

Who is more foolish, the fool, or the fool that posts on this forum.  [whacko]