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Red Dot Optics - Question


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Just like a weapon, the application drives the choice of a sighting system. A scope is generally a long range sighting device, target shooting, hunting etc. A reflex, holo sight or a laser is a combat or SD sighting device.

For LE or Military the holo sight, reflex, or a laser has an advantage for clearing houses or quickly engaging a target at short distances. The higher end holographic sights like the Eotech are also parallax free. With your head up, both eyes open, weapon at the ready, this gives you the ability to quickly put rounds where you want them to be without shouldering the weapon and aligning your eye with a conventional sighting device.

SD and SHTF are the same thing, for that I would choose a holo sight, for target shooting I want a high quality scope with a lot of power. Use a picatinny rail as your optic mounting platform and you can swap optics depending on your application.

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One more thing is why dont you guys try the scopes that were designed with AR'S in mind like the one i own Nikon m223 1-4x24 point blank reticle, if you are shooting at with 1x magnification it works as easy as an red dot sight there is almost no eye relief issues with it and if you want some more range just put it on 4x and is great at 100-200 yards that is what AR was designed for.

that way you dont have to mount a scope and an off set red dot sight - it just adds additional unnecesary weight to it.

try that scope it is very good and the price is not bad around $250 - 300. hope this helps.

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Some non-Eotech sights are called holographic and I suppose the ones so-named are parallax-free but dunno from personal experience.

The "reflex" sights I've tried do have some parallax but that doesn't make em useless. Perhaps the small-diameter long-tube reflex sights like some which are popular with target pistol users, might be "better" because the small diameter and long tube limits how bad the parallax can get. But that is only a wild guess possibly wrong.

Have noticed that if one doesn't get the dot exactly in the center of the barrel on a reflex sight, there can be significant aiming errors. I find it more difficult to make sure the dot is well-centered in a large-diameter reflex sight but folks with more skill would not have problems, and maybe even if the dot is severely non-centered it is still good enough for short-range defense shooting. Haven't tested that but it would be an interesting test.

Just sayin I really like the Eotech because it seems easier for me to aim them. Also have a bushnell "made under license by eotech" old model that works good, though the sight window isn't as big in my model of bushnell. No big deal. Only a couple of older bushnell models were "eotech clones" AFAIK.

What are some of the other brands of holographic sights that are resonably durable and are as easy and parallax-free to aim as the eotechs?

As an aside, maybe some of the chinese eotech clones are holographic, but was examining one eotech clone at a gun show that had very similar external appearance to an eotech sight but fiddling with the sight it appeared to be a reflex sight rather than holo, but maybe I was mistaken. I'd aim the clone at a test point then move my head around, and the dot would drift off target like with a reflex sight.

Edited by Lester Weevils
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A quality RDS's battery will last quite a while. AimPoints can last up to 80,000 hours. Even a tenth of that would be good for me.

Once a RDS is zeroed, it doesn't matter where it is in relation to the barrel - especially for close in shots. Anyone remember EOTech used to have that picture of a broken lens with the reticle in the top right?

The Army quals everyday with RDS out to 300m. With practice, you can reach out further. It's already been said a couple times but the mission drives the gear. Closer in shots? - RDS. Longer range? - rifle scope.

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One more thing is why dont you guys try the scopes that were designed with AR'S in mind like the one i own Nikon m223 1-4x24 point blank reticle, if you are shooting at with 1x magnification it works as easy as an red dot sight there is almost no eye relief issues with it and if you want some more range just put it on 4x and is great at 100-200 yards that is what AR was designed for.

that way you dont have to mount a scope and an off set red dot sight - it just adds additional unnecesary weight to it.

try that scope it is very good and the price is not bad around $250 - 300. hope this helps.

That is where I went too. I use the leopould mark AR, 3-9 power and did not fool with an offset red dot --- I can do what I need to with it.

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A quality RDS's battery will last quite a while. AimPoints can last up to 80,000 hours. Even a tenth of that would be good for me.

Once a RDS is zeroed, it doesn't matter where it is in relation to the barrel - especially for close in shots. Anyone remember EOTech used to have that picture of a broken lens with the reticle in the top right?

Yep the holographic sights are my fav just because my eyes are not good. The EOTech doesn't much care where the dot is in the sight window. Those use a laser to drive a holographic grating.

http://en.wikipedia....ki/Reflex_sight (re reflex sights not specifically holographic sights)

Since the collimated image produced by the sight is only truly parallax free at infinity, the sight has an error circle equal to the diameter of the collimating optics for any target at a finite distance. Depending on the eye position behind the sight and the closeness of the target this induces some aiming error.[21] For larger targets at a distance (given the non-magnifying, quick target acquisitions nature of the sight) this aiming error is considered trivial.[22] On small arms aimed at close targets this is compensated for by keeping the reticle in the middle of the optical window (sighting down its optical axis).[23] Some manufactures of small arms sights also make models with the optical collimator set at a finite distance. This gives the sight parallax due to eye movement the size of the optical window at close range which diminishes to a minimal size at the set distance (somewhere around a desired target range of 25-50 yards).[24]

Perhaps many ordinary red dot reflex sights have a position independent dot, but my two ordinary red dot sights are position dependent. It is easy to verify-- Ferinstance mount the sight in a vise on the shop bench and aim the dot to a spot on the far shop wall. Works best if the far wall is 20 feet away or better. Then move yer head side-to-side, up-n-down, and the dot doesn't stay centered on target. The dot moves off the target according to its location in the view. For longer range testing one could mount the red dot on a camera tripod and test the parallax at longer distances outside. Some parallax is "unavoidable" at real close distances, but my old 40mm BSA (same design as numerous other barrel red dots including some Nikon models) and my Konus 20mm "sig clone mini dot clone" both have significant errors if the dot is not centered. OTOH batteries last a long time in them and they are excellent sights as long as you aim with the dot in the exact center of the view.

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Edited by Lester Weevils
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I have used RDS's at spitting distances of people and it didn't matter one iota. Whatever small amount of parallax exists isn't going to make a difference up close, which is the intent and usefulness of a RDS. Reflex shooting made easy. I'll be going to the range tomorrow or monday so I'll give your test a little try.

I have no idea about clone optics. My experience has been with AP's and EO's and the piggybacked Doctors/JPoints.

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lots of thought went into some of these replies, for the wife still learning about long gun shooting a red dot (eo tech) me a poor teacher plus her being right handed and left eye domint. i for myself must agree with scope. i use a 1 x 5 at 1 power its both eye open. just a note i most always shoot both eyes open no matter the power of the optic. 5x is plenty good for breaking clays out 400 and 6" and 8" steel alittle futher. i did not care for the Nikon 1x 4 223 scope the crosshairs to big. i have not had my hands on the Leupold AR scopes but in a discusion with a rep he said that because at that time i was using VX-3 i would not like the glass on the AR series-hint the lower price.

i hope to get a 1 x 6 in a year. the leupold 1 x 8 way to high $$$ for me and in the FFP at 1x just did not care for. if you have to have a battery you can still have that in a scope also.

i have hunted with the eo tech for me it really sucks in low light, no not the dot, the light gathering.

in the end its what you use best and only you know that. being a prior service sniper this seems like a odd question for you to ask. as you already know the anwser. good luck and have fun.

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........then you have the people who wear glasses and/or have bad sight in general. I personally have given much thought to my situation and abilities. I wear glasses and IF the glasses are broke, I couldn't see much past 100yrds anyways. If I can't see it, I can't hit it. Therefore, the terrain I'm surrounded with and my "semi-disability" of sight issues, I decided on an Aimpoint. I have tried many different RDS and the Aimpoint does it for me. While one could argue that fact that with a scope one could easily see distances without glasses, I doubt I'd have time to "scope" out the terrain while on the move and doubt I'd even be able to see or hit something out that far. 200yrds or less is what I'm confortable with.......I can't stay still for long so I'd always have to be on the move anyways. To tag me, you'll have to snipe me. I wouldn't know if it happened so I'm good with that......

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Perhaps many ordinary red dot reflex sights have a position independent dot, but my two ordinary red dot sights are position dependent. It is easy to verify-- Ferinstance mount the sight in a vise on the shop bench and aim the dot to a spot on the far shop wall. Works best if the far wall is 20 feet away or better. Then move yer head side-to-side, up-n-down, and the dot doesn't stay centered on target. The dot moves off the target according to its location in the view. For longer range testing one could mount the red dot on a camera tripod and test the parallax at longer distances outside. Some parallax is "unavoidable" at real close distances, but my old 40mm BSA (same design as numerous other barrel red dots including some Nikon models) and my Konus 20mm "sig clone mini dot clone" both have significant errors if the dot is not centered. OTOH batteries last a long time in them and they are excellent sights as long as you aim with the dot in the exact center of the view.

I was tasked to give a class on the 68 to a bunch of people who have never used/most likely never seen one....here's something relevant I found in the TM. -

THEORY OF OPERATION

The M68 sight is a reflex (non-telescopic) sight. It uses a red aiming reference (collimated dot) and is designed for the “two eyes open†method of sighting. The dot follows the horizontal and vertical movement of the gunner’s eye while remaining fixed on the target. No centering is required

Outside of 50m, there should be no parallax. Inside of that, you should be able to hit what you're aiming at regardless.....or you deserve the consequences. This manual is for the AP but there should be no difference with the EOTech either. One a quality optic is zeroed, it's zeroed.

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Thanks scoutfsu

Perhaps the example devices I have used do not have "perfect enough" optical surface or design. Ain't making claim about items I've never used/tested, only reporting my experience.

Ferinstance if I "manually bench rest" one of my eotechs aimed about 20 feet away, then move my head vertical and horizontal to test the dot behavior in the periphery-- The Eotech dot barely moves off target horizontally between the extreme left edge and extreme right edge of the view window. But the Eotech dot moves "maybe an inch" off target vertically between extreme top edge and extreme bottom edge of the view windows. It was just a brief re-test before posting this message. I didn't tape a target or ruler on the wall and did not remove the sight from the gun and clamp it down in a vise or tripod. So these are "approximate" measurements. Maybe I'm doing something wrong but this is what I see--

The 40mm BSA moves maybe +/- 2 inches off target vertically between top and bottom edge. It moves about + 2 inch to the right edge relative to center but it "runs away" going to the left of center, and looks about 4" off target at the extreme left edge.

The Konus Mini-Dot has about +/- 2" horizontal movement, and about -2" movement from center down to the bottom edge. But it "runs away" going above the center, and looks about 4" off target at the extreme top edge.

So the two LED reflex sights have lots more parallax error than the Eotech laser holographic, at similar distances. In fact the tiny Konus and the big BSA have similar magnitude of error. The Konus has the LED on the bottom of the shell and "runs away" with the worst error at the top of the display. The BSA has the LED on the right side of the shell and "runs away" with the worst error at the left of the display. So the "nature" of the error seems identical, with the worst error at the biggest reflected viewing angle of the LED.

Dunno if the nature of the problem is the same, but even though the Eotech has much better performance, it has more parallax in the vertical than horizontal, and the laser is in the bottom of the device. So the parallax in the Eotech may also have to do with the steepness of the reflected angle. However the vertical parallax in the Eotech doesn't seem to "run away" at one or the other extreme. It seems a very linear small parallax shift over the entire vertical range.

Dunno if a laser holograph is "just naturally" less likely to show parallax, or alternately perhaps the eotech is more "perfectly designed and assembled" than my inexpensive LED reflex sights. Have had a couple of other inexpensive LED reflex sights (for telescope use) which performed about the same as the two cheap gunsights. But never had a $500+ LED reflex sight to test. Maybe the expensive LED reflex sights perform as good or better than the eotech regarding parallax. Would be fun to play with some of the expensive ones to find out.

An inch or two of error may be meaningless for making war, but I was using the cheap red dots for .22 pistol plinking typically 15 yards. My accuracy never was good but is worse nowadays. At one time it wasn't foolish to shoot at a 8.5 X 11 sheet with 6 targets printed on it. Whichever target on the page I was aiming at would get most/all of the group. Even an inch of error is a big deal in that situation, even it if is only "for fun". Especially if you let the error take all the fun out of it.

Dot sights are really nice and I like em. On a rifle it is pretty easy to keep the dot in the center of the view and I use the cheap LED dot sights on rifle nowadays and it works good. Finally decided even though my shooting gets worse all the time, I can shoot the Ruger Mark II better with iron sights on a sunny day, than with the cheap red dots. Haven't tried an Eotech on the Mark II. Ought to try that sometime to see if that works better than the cheap red dots. Am expecting that it would work better, but no telling without trying it.

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I only have a couple of electronic/holo sights, the first is an el'cheapo BSA 30mm tubed "red dot" one is on a Ruger MKII (10" barrel target model) that I slapped on there just to help with making my target aquisitions & target transitions a little quicker for the various shooting games we used to play, it works ok for it's intended purpose but I wouldn't trust it for anything other than having fun with at the range.

The other is an Eotech XPS 2 that I tossed onto a 7" barreled SBR'd AR to help off-set the short sight radius, in my experience with the two different electronic/holo sights (aside from the obvious quality/durability differences) the additional 65MOA outer circle makes target aquisition & transitions even faster than the standard "red dot" does, I honestly wish that I could afford to buy a few more XPS's.

As far as washing out in bright day light, I generally have to turn the BSA dot to it's brightest level & even then it will still tend to wash out at certain angles, the XPS is a whole lot better in that regard but I do still occasionally have to thumb the brightness up to compensate.

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I have two of the "least expensive" eotech 511.A65 and like the stubby size and think the basic function of the sight is about the same as more expensive models, except fancy features like night vision capable or extended battery operation or whatever.

Found a bushnell "licensed by eotech" holographic pretty cheap "old stock" in a shop-worn box from a gun store dealer's table at a gun show. Maybe the bushnell was used but think it had just sat on a shelf a long time without getting sold given the fairly high retail price compared to cheapie red dots. It didn't have any marks on the anodizing like it had ever been used on a gun. Bought it at least a couple of years after bushnell quit selling/shipping that model. The bushnell works "just as good" as the 511's as best I can tell though it is a longer-lower design with a "less tall" view window than the eotech, but about the same width. But even the smaller view window is still lots easier to see than iron sights. A fella probably wouldn't want to take the bushnell into a war zone as it most likely is not as rugged as eotech, but hasn't broke yet for hobby use.

They don't make the 511.A65 any more. Mine are the "latest revision" of that model and I like em fine except they eat batteries in a few weeks if they just sit turned off. That model and possibly a random few other eotech units were notorious for eating batteries. It would be nicer if they didn't eat batteries, but its no big deal for an amateur to take out the batteries every time before the guns go back in the safe. At first I thought the bushnell didn't eat batteries turned off but was fooled because the bushnell takes a lot longer to drain them. They need to sit in the safe turned off for 6 months or a year before going dead. So I store that one without batteries as well. The two cheap red dots never run down batteries turned off and the little coin cells last forever with occasional use. But they don't have auto-turn-off so they will certainly run down batteries if you forget to turn em off before putting them up.

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They don't make the 511.A65 any more. Mine are the "latest revision" of that model and I like em fine except they eat batteries in a few weeks if they just sit turned off. That model and possibly a random few other eotech units were notorious for eating batteries. It would be nicer if they didn't eat batteries, but its no big deal for an amateur to take out the batteries every time before the guns go back in the safe. At first I thought the bushnell didn't eat batteries turned off but was fooled because the bushnell takes a lot longer to drain them. They need to sit in the safe turned off for 6 months or a year before going dead. So I store that one without batteries as well. The two cheap red dots never run down batteries turned off and the little coin cells last forever with occasional use. But they don't have auto-turn-off so they will certainly run down batteries if you forget to turn em off before putting them up.

The 511/551 models use the N size battery. EOTechs in general are notorious for killing batteries but that type was probably the worst offender. The 512/552's were a close second. Keep a good watch on your battery compartment. The contacts have a tendency to fall out. Your best bet on batteries is to use the lithium type. They're more expensive but they'll last longer and don't have as many problems as cheap batteries.

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Guest profgunner

Picked up an EoTech SU-231/PEQ today. Probably more capabilities (NV, submersion to 60 ft, etc.) than I need but it has a very nice sight picture. From everthing I see it looks like its of very good quality.

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