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Page AR-15 » Optics, Mounts, and Sights
AR Sponsor: bravocompany
Posted: 5/4/2004 8:50:59 AM EDT
Background -

One thing I do not like about telescopic sights is the need to place your head in a specifc, very restricted location in order to use the sight.  This is due in part to their limited eye relief.  It is also caused by the limited view angle - your eye has to be exactly in line with the optical axis plus or minus a small amount (approximately an inch) or you cannot see the reticle and paralax errors start to become an issue.

Questions -

Does an EOTech have infinite eye relief?

How far off angle can you go and still see the reticle?

Are there any paralax errors iwith an EOTech if you are off axis?




P.S. - this LOOOOOONNGG wait for the EOTech rev F's is killing me.  I'm actually contemplating buying an Aimpoint!
Link Posted: 5/4/2004 9:06:38 AM EDT
[#1]
Mike,

EOTech has infinite eye relief; mount it as close or as far from your eye as you like.

I have placed 25 yard shots to torso size targets with only half of the reticle in the optic window.  Forest at Maryland AR15 has found if you keep the entire reticle in the optic window, anywhere within the optic window, your parallax mistake will be minimum.
Link Posted: 5/4/2004 10:35:12 AM EDT
[#2]
Thanmks for that info, SMGLee.

Here's another question:

Does an EOTech fit securely on the gas block rail of a RRA Varmint  A4?
Link Posted: 5/4/2004 10:41:13 AM EDT
[#3]

Quoted:
Does an EOTech fit securely on the gas block rail of a RRA Varmint  A4?





Appears like there is enough room to mount it up there, the actual bitting anvil isn't but about 3/4" long IIRC. If the handguard doesn't interfer........

FWIW, never heard of anyone mounting it way up there, but hey it might work ya.

Mike
Link Posted: 5/4/2004 10:48:49 AM EDT
[#4]
I've never heard of it , either.  When I picked up the upper this morning, it seemed like a natural spot for it (watch how many people are putting long rails on their rifles).  This spot is "built in" on this short carbine upper.  

Another whacky idea I had was to put my front iron sight out at the muzzle to maximize sight radius on this short carbine upper (using a barrel band).  See my other thread on this idea.
Link Posted: 5/4/2004 11:06:57 AM EDT
[#5]
The only reason that I wouldn't want to mount an EO Tech on the gas block would be because it would be a bit of a stretch for me to reach the control buttons while the rifle was shouldered. Also, IIRC, the further away the sight is from your eye, the bigger the reticule appears to your eye. What that means is the reticle will cover more of the target, especially at longer ranges. Or something like that.
Link Posted: 5/4/2004 11:15:55 AM EDT
[#6]
That gas block rail is much lower than the receiver flat top rail, which is what the EOTech is designed to mount to.  It may work, but once zeroed, the reticle will be high in the EOTech's window.  The weight of the sight that far forward will definitely change the balance of the rifle, probably making it slower to move the muzzle between targets.  Finally, with the reticle that far forward, eye alignment and cheek weld will become more critical, which also might slow you down.

But hey, if it works for YOU, go for it.

Editted to add:
The further away your eye is from the EOTech, the larger the reticle appears in relation with the window.
Link Posted: 5/4/2004 12:20:29 PM EDT
[#7]
Is EOTech placement really a personal preference or should it be placed more towards the front of the rifle. I mounted my OTAL on the side of my SIR so that I could mount my EOTech farther forward (as recently stated in my post). However, in the new Guns & Weapons magazine they show a Barrett M468 with an EOTech mounted way back by the charging handle. What is everyone's input on this. Any pics will help too. Here is my setup.

Link Posted: 5/4/2004 12:42:29 PM EDT
[#8]
I have mounted an OKO on the gas block of an Armalite 20" in order to use it through a magnified scope for shooting at night.  It worked just fine, but then an OKO is only 2 or 3 ounces.

It's probably not something you'd wanna do, BUT the Yankee Hill modular free float tube would be perfect for what it sounds like you're trying to do.  You could put one 4" rail on the top anywhere along the tube and place the EOTech wherever you wanted it.

YHM Modular tube from Bright Flashlights

OR, since your current float tube looks low enough, you could just mount the EOTech as far forward as you can get it on the flat-top like SMGLee does and be done with it.  I personally feel that's where you get the best "balance-to-distance" ratio.
Link Posted: 5/4/2004 4:53:46 PM EDT
[#9]
Placement is personal preference.  If you mount it forward, you have a wider FOV view as the optic body is lees obtrusive.  However, it will be more front heavy.  In the end, use it where you feel the most comfortable with it.
Link Posted: 5/4/2004 7:34:12 PM EDT
[#10]

Quoted:
Is EOTech placement really a personal preference or should it be placed more towards the front of the rifle. I mounted my OTAL on the side of my SIR so that I could mount my EOTech farther forward (as recently stated in my post). However, in the new Guns & Weapons magazine they show a Barrett M468 with an EOTech mounted way back by the charging handle. What is everyone's input on this. Any pics will help too. Here is my setup.

www.imagestation.com/picture/sraid114/pd5115ff23d8bc09cb07d068ce1cf9ca0/f8d6c325.jpg



The actual reason optics are sometimes mounted out far is in order to place NV optics behind them. If you don't have Night Vision, then you don't need to put all that space between you and your optic.
This is how it was explained to me when I asked the same question in a military course I was taking.

MASTER BLASTER

Join Army Special Forces! Ask me how.
Link Posted: 5/5/2004 7:55:44 AM EDT
[#11]

Quoted:
Placement is personal preference.  If you mount it forward, you have a wider FOV view as the optic body is lees obtrusive.  However, it will be more front heavy.  In the end, use it where you feel the most comfortable with it.



Hmmm. My experience is the further back you put it the more the "hood" ghosts out.  With it mounted as far back as possible and your nose on the charging handle the hood completely ghosts out and it looks just like a dot floating in space. I loved it there but ultimately chose to move it a bit forward in order to make room for my BUIS.
Link Posted: 5/5/2004 10:04:49 AM EDT
[#12]

Quoted:

Quoted:
Placement is personal preference.  If you mount it forward, you have a wider FOV view as the optic body is lees obtrusive.  However, it will be more front heavy.  In the end, use it where you feel the most comfortable with it.



Hmmm. My experience is the further back you put it the more the "hood" ghosts out.  With it mounted as far back as possible and your nose on the charging handle the hood completely ghosts out and it looks just like a dot floating in space. I loved it there but ultimately chose to move it a bit forward in order to make room for my BUIS.



Yes, it "ghosts", but it is a rather large blur, whereas further out, it is a smaller object in your FOV.
Link Posted: 5/5/2004 1:21:04 PM EDT
[#13]
I have been trying to use my eotech as a rear sight, still using the front sight. It works okay, I think I need to use it farther up. Anyone try this? I have a flattop, with quad rail. do I need to get the eotech up over the front sight?
Link Posted: 5/5/2004 2:07:24 PM EDT
[#14]

Quoted:
I have been trying to use my eotech as a rear sight, still using the front sight.



WHY??? You lose all the advantages of the sight by doing this.



do I need to get the eotech up over the front sight?

No you just need to look over the top of the sights - you'll still see the reticule.  Put dot where you want the bullet to go and squeeze the trigger.
Link Posted: 5/5/2004 2:35:05 PM EDT
[#15]
Is the accuracy consistant? The recticle moves when I move my head.
Link Posted: 5/5/2004 5:25:13 PM EDT
[#16]
"Is the accuracy consistant? The recticle moves when I move my head."

SMGLEE mentioned that he did a test and purposely fired with the reticle at different locations in the window, and as long as the 65MOA ring was fully within the window the POI was UNCHANGED

If the 65MOA ring is partially out of the window, it will not shoot exactly the same POI.  

I don't think that is too big a deal, as the window is so big you have to be really trying to get the 65MOA ring to start to leave the window.


focus on the target, not the reticle, or the front sight, that's the whole point of REFLEX
Link Posted: 5/5/2004 5:25:25 PM EDT
[#17]
you can probably tell by my pic that the iron sights don't co-witness with the EOTech on a SIR #45 b/c the EOTech sits up too high (no big deal to me). If I had the #50 it would be fine but it wasn't out at the time. Anyways I haven't shot it yet since I moved it forward. I'm going to see how I like it. If it seems to front-heavy I may move it back a tad.
Link Posted: 5/5/2004 5:30:43 PM EDT
[#18]

Quoted:
Is the accuracy consistant? The recticle moves when I move my head.



The reticle looks like it is moving but it really isn't. It is supposed to move when you move your head incase part of the glass is obscured or cracked or something. EOTechs work like a HUD on a fighter jet.
Try this:  Keep the gun steady and aim at a target. If you move your head the reticle moves with you but notice that it stays on the target and does not move off the target unless you move the gun (not your head).

This pic may help explain.

Link Posted: 5/6/2004 7:50:15 AM EDT
[#19]

Quoted:
Is the accuracy consistant? .


That depends - do you consider one ragged hole @50y consistant shooting??

The whole point of these sights (and Aimpoints) is you can move your head and the reticule will still aim true.
Link Posted: 5/6/2004 7:51:33 AM EDT
[#20]

Quoted:
SMGLEE mentioned that he did a test and purposely fired with the reticle at different locations in the window, and as long as the 65MOA ring was fully within the window the POI was UNCHANGED



The rest of your post was spot on - but I was the one who performed the tests (not Chen - he's too busy doing other cool things).
Link Posted: 5/6/2004 8:42:59 AM EDT
[#21]
Thanks for the good info guys!
Link Posted: 5/6/2004 2:09:23 PM EDT
[#22]

Quoted:
Is EOTech placement really a personal preference or should it be placed more towards the front of the rifle. I mounted my OTAL on the side of my SIR so that I could mount my EOTech farther forward (as recently stated in my post). However, in the new Guns & Weapons magazine they show a Barrett M468 with an EOTech mounted way back by the charging handle. What is everyone's input on this. Any pics will help too. Here is my setup.

www.imagestation.com/picture/sraid114/pd5115ff23d8bc09cb07d068ce1cf9ca0/f8d6c325.jpg



How much does that dude weigh, anyway???
Link Posted: 5/6/2004 4:38:13 PM EDT
[#23]
Dear SMGLee,                         (Remember Dear Abby?)

I've been shooting 3-gun matches for just two years using an EOTech.  Most of the matches have  targets that are under 50m.  I have my EOTech zeroed out to 100m.

I find that if I shoot over 200m my dot starts to cover the target.  Out to 300m I don't even see my target.  (Maybe it moved?)

Is the EOTech designed to go out to 300m or was I given the wrong info or is it my eyes.  I do wear vision corrected glasses.

I shoot quite well when I put on my ACOG TA01NSN out to that distance.  But.............since I can't do it with my EOTech I was wondering is that scope really designed for that distance?

Your comments are appreciated.  Sincerely.



Page AR-15 » Optics, Mounts, and Sights
AR Sponsor: bravocompany
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