hey i was wondering, if i hold my rifle sideways or upside down, will my poi still be where the reticle is on? you know how you move you head the the reticle moves and floats inside the box. will it stil hit the target with me not getting a good aim?
No.
The eotech is like every other rifle sighting system in the world from iron sights to high magnification scopes. That is to say that when you zero it, you are taking into account the reticle’s position in relation to the bore. So if it’s 1.5"(just as an example) over the bore when you zero it and turn it on it’s side, you will now be hitting 1.5" left and 1.5" high…and this gets greater as the distance increases.
Also remember that the position your head is in with regards to the optic would need to remain constant to the optic for it to remain even that close…things can start getting really screwy as your head/eye position starts to change in various positions.
As the reticle floats inside the box as you mentioned, it is not remaining constant to the target…I don’t care what their marketing says. Move your head, move your point of impact. It IS NOT keeping the POI the same.
I have to respectfully disagree. When move your head, yes, the reticle appears to “float” but it is staying on target. The target appears to be “floating” also. Just because you move your head in relation to the EOTech, that doesn’t mean it loses its zero. For example, say the rifle & optic are sighted in at 50 yds. If you shoulder the rifle quickly & don’t get a perfect cheek weld & the reticle is perceived to be off center but still on target, it will still be poa/poi.
The EOTech reticles are a same plane RDS which means the reticle appears to be projected onto the same plane as the target.
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This is incorrect. All RDS’s have a POI shift when the dot is not centered in the middle due to parallax.
We just covered this in Pat’s TAPS class (AAR here: https://www.m4carbine.net/showthread.php?158688-Pat-McNamara-TAPS-AAR-Ohio-2014)
Try this experiment, put up a target (like the NRA B8 repair center) up at 100yds. Shooting prone, put your head in a position where the dot is in the upper right hand corner, but STILL on the black. Fire 5 rounds and see where your bullets impact at.
C4
When you hold it sideways (for instance), your windage and elevation basically switch. If lying on your right side (urban prone), you will need to hold about 3-4 inches to the LEFT of your intended aiming point and vice versa when you shoot from your left side.
C4
I wasn’t accounting for any parallax shift. Various RDSs have varying degrees of parallax shift but it’s not like you’re seeing the same amount poi shift in relation to the amount the reticle appears to move or “float” about in the FOV, which is what I had assumed the OP was asking about.
I should’ve added a disclaimer regarding any parallax shift vs poi shift. My mistake.
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Yes, it varies quite a bit. According to Mac, the Trijicon RMR has the most and the Aimpoint Micro series has the least. The EOTech is somewhere in the middle.
At closer ranges (inside 50yds), you might not see a lot of parallax shift, but at 100yds, it can take you completely off target.
I understand what you are saying now, but didn’t want the OP to think that the red dot could be ANYWHERE in the window and the bullet was still going to impact exactly on the dead center of the target.
C4
I can’t account for what Mac said and I certainly don’t want to step out of my lane but research I’ve done is that parallax is more of a result of the technology behind the RDS. Holographic RDS’s (from what I’ve read) produce the least amount, if any, parallax. EOTech advertises their products as “parallax free”. (Who am I to dispute either way?) This is why I didn’t take any parallax into account in my post. When two lenses with a reflective surface are used as the technology for an RDS, the parallax shift is greater (again from what I’ve read but I’m not qualified to dispute otherwise either). Parallax does rear its ugly head at greater ranges I certainly agree. Personally, I know that my skills, or lack thereof, will impact poa/poi much more than any parallax of a quality RDS. 
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Most every RDS advertises “parallax free.” This is a lie as they are not at ALL distances.
C4
Yeah, I was just researching some of this on Aimpoint’s & EOTech’s websites. I’m having issues copy/pasting from my phone so I’ll just provide links to their respective pages where they touch on the reticle vs FOV.
http://www.eotechinc.com/holographic-weapons-technology/holographic-sight-versus-red-dot-sight
http://www.aimpoint.com/us/products/whyreddotsight2/
Both state that their optics are POA is POI regardless of reticle position. If they both are indeed truly parallax free at a certain distance, then that would be the case. Are they both parallax free? Are they both lying? I can’t say either way.
As for the OP’s question, I still say yes, the reticle can float about the FOV & still be on target BUT, as Grant clarified, any parallax will affect POI.
Another thing I read was that parallax gets less at greater distances which goes against what my gut says. Or am I confusing that with the effects of parallax on POI at greater distances? Can anyone clarify?
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They are both parallax free at a certain distance. The number I have always heard it is past 15yds. I would have to test it to verify though.
Another thing I read was that parallax gets less at greater distances which goes against what my gut says. Or am I confusing that with the effects of parallax on POI at greater distances? Can anyone clarify?
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If you look at the target below, I shot my T1 at 100yds with the dot buried all the way in the top right corner (while still having the dot on the center of the target). Group shift was consistent at 1 O’Clock from POA at around 6-7 inches.
C4
It’s good enough at close distances, but at longer ranges you start to get the effects of rifle cant. If you’re shooting with a left lean, your bullet will tend to fall low and left. Vice versa for rightward cant. Upsidedown, and your bullet would just impact low, i.e. hit the bottom of the target or miss low at distance.
Paralax is somewhat negligible for RDS systems because it’s problematic at greater distances. Distance can give you more time to build a better shooting position.
I don’t doubt your results. I just read some statements online from EOTech employees that the EOTechs were “designed to be parallax free from 100yds to infinity” but had greater parallax error at closer ranges. I would’ve thought that to be the opposite, similar to your results. Given that your were using an Aimpoint and with its different technology, it’s likely to be an apples/oranges thing, which is probably where my confusion comes.
I’ll have to try that test with both my Aimpoints & EOTechs to see if their respective technologies perform better at one distance vs another, say 25 vs 100.
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See, that’s what I’ve always thought too but the more I read online, the more I see people saying that it’s worse at closer ranges.
Here’s a quote from an EOTech tech support taken from another site:
“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."
Do halo sights act differently than other types of RDSs with respect to parallax? Is one better than another at close range? Long range?
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Had a long conversation with Aimpoint about this thread. Aimpoints (and I assume EOTech’s) are supposed to be parallax free at 15yds and past. So I asked them about my target and they referred to it as parallel infraction. New term for me. They also thought there could be a difference between Micro to micro based off of how the lens sits inside the body. I have several micro’s and will have to test this theory out.
Another interesting point they brought up is the importance of making sure that the dot is in the DEAD CENTER of the window when zeroing (as it can affect POI at greater distances). I think most people pay little attention to cheek weld with RDS’s, but apparently it does matter.
C4
Most people are so retarded they can’t grasp sight over bore. So having them think about paralax too is a futile exercise in futility.
I’ve been playing with this at home since I just bought a new Eotech to try out. 1.3" or so on EVEN a head shot is still not going to equate to a miss.
Maybe it’s just that I’ve had some precision rifle instruction… but that strikes me as common sense.
I’m obsessive about stuff like that, and also with reconciling my BUIS to my RDS. Nothing drives me more nuts than to pick up some guys gun where the dot is way off to the side of some irons.
Even if you don’t take parallax into consideration, there is still the issue of height of the sight system, iron or optic, over the bore axis. Take a standard AR with iron sights, which has a sight plane 2.6" over the bore axis, and practice canting the rifle at 50 meters. You will see a noticeable difference in POI.
We do some of the drills Grant made reference to during the carbine course to show how far from POA the rounds will impact when the dot or reticle is not centered in the optics glass. It may be “close enough for government work” inside the shoot house, but not at greater distances.
Common sense isn’t so common. That is why I posted it (to make sure everyone sees it).
Same goes with zeroing. A 100yd zero is going to give you a MUCH more accurate zero at 200 and 300yds than a 50yds zero does. If you do use a 50yd zero, you MUST check it 100yds and 200yds and then make adjustments and then RE-CHECK it at 50yds. Few people do this.
C4
These are all the reasons I use a fixed front sight with my Eo’s. It gives you a quick point of reference to ensure the dot is centered. While it may not matter much during heads up shots past 50yds, it really helps when things positions get “weird”.
Also the easiest way to remember the holdover on a canted rifle is high to the magazine side. How much holdover depends on how much cant and distance to target. Just something you gotta play around with, on paper. At 100 yards the offset can be as much as 6-8" which will still get you shots on steel, but paper tells the ugly truth.