Aimpoint Comp M2 2x parallax

[milcaztra]

I just received an Aimpoint Comp M2 2x, which I'm planning to mount on a DSA carbine when the mount arrives. Having never tried a 2x Aimpoint, I quickly installed the battery and cranked up the knob. Very nice.

Sitting on my couch, I checked it out and discovered a problem. When I moved my head, the dot moved too. Hmmmm, I thought --- this doesn't happen with my EOTech or any other Aimpoint with which I have jacked, so there's something wrong: parallax. I put the M2 2x on my desk and taped a ruler to the wall about 10 feet away. Shifting my head so that the dot moved from the far left to far right border of the reticle, parallax put the shot in a 2" circle at 10 feet.

But I was still thinking that good quality red dots aren't supposed to have parallax, so I checked Aimpoint's website, various other red dot ads, and HR's and TFL's archives, and every article said that good red dots don't have parallax, so is it just my luck (bad) kicking in?

Or is there something to magnification that creates parallax? I checked the Leupold Mark IV red dot specs --- the specs say that the Mark IV's parallax is factory adjusted for 150 feet and nonadjustable by the user. Does this mean that at 150 feet, the Mark IV has no parallax? Does this further mean that with my Aimpoint, at farther distances, the parallax will decrease until I get to Aimpoint's designated parallax-free distance?

I'm hoping that someone can enlighten me. A 2" circle at 10 feet is plenty good --- I just have to remember that for surgical placement at close distances, the dot goes in the center of the reticle, about 3" above the intended POI, with a noncanted weapon, except on Thursdays under the full moon.

But I'd still like to confirm that magnified red dots do indeed have parallax. Thanks for your thoughts!

 

[Chris Rhines]

All dot sights have some degree of parallax. Part of the design.

- Chris

 

[milcaztra]

I think that I'm misunderstanding the idea of parallax. I thought that good red dots were supposed to be nearly parallax free. The advantage to having near-zero parallax would be that in high stress situations, the head/eyes may not be in perfect relation to the optic; so POI = POA even if your eyes are off line. So, I thought that the less parallax the better. Am I wrong? I'm just trying to figure out why the 2x shows so much more parallax than my EOTech. Did I get a bad unit or do magnified red dots inherently have more parallax than nonmagnified scopes? Thanks for the feedback.

 

[RussB]

Aimpoint M2's have NO parallax, none, NADA!

I've never checked out the 2X...maybe you should contact Aimpoint.

a relevant link @ AR15.com
arfcom link

 

[KW]

Theres a thread over on AR-15.com talking about the same thing with the EOtech. It seems that there is a little bit of parralax at short range, but it's barely noticeable. I wonder if the 2x magnification of the aimpoint makes it more noticeable.

 

[uglygun]

Two things to consider.....


At closer ranges, parallax concerns can be over exagerated. I've seen what I believed to be parallax from EVERY red dot sight I have ever handled when testing for it at closer distances. Try to construct a test with distances of over 25 yards, if possible try putting it through a live fire test on a target at 100 yards.

The other thing that comes to mind, it could have to do with the magnification factor of the Aimpoint 2x you are using. It shouldn't be a huge amount but I can't help but think that a magnifying optic has to have atleast some degree of parallax. Something worthy of debate possibly.


I've put my Trijicon Reflex NSN through the test and found that depending on how I use the sight, I will experience some parallax but it is pretty minor. The issue with my Reflex NSN revolves around whether you are forced to black out the polarizing filter and use it as an OEG(occluded eye gunsight) or if you can leave the filters open, depending on how your brain merges the target I believe there is room for error and parallax.


As for my Aimpoint Comp M, it does much better and appears to be immune to parallax at longer distances or atleast it's very minor.

 

[nemesis]

When I moved my head, the dot moved too.

Do you mean that the dot moved across the field of vision? It will do that but the round will always impact where the dot indicates, regardless of the dot's position in the field of view. Or did you mean that the dot moves from the aimed point? It shouldn't do that and there is almost no parallax in an M2 sight.

My AR Carbine/M2 can be fixed in position and the dot stays on the intended target as I move my head but the dot can wander all over the field of view. The really nice thing is that you don't have to be lined up directly behind a centered dot. As long as the dot is on the intended target, it will hit it.

 

[DMK]

I don't know the answer, but in trying to figure it out myself, I found this interesting page (look about 3/4 of the way down):

http://www.ar15-rifles.com/aimpoint.shtml

 

[milcaztra]

Thanks for the replies! That's an interesting link with the three illustrations. My 2x Aimpoint seems to follow the third example. The dot changes its placement by 1" each way on the target when I move my head right or left.

Let me explain better what I did: I put the scope on my desk so that it would be stable and the POA shouldn't shift, and I taped a ruler to the wall about 10 feet away. I then placed the dot, centered in the reticle, exactly over the 6" mark. I moved only my head right and left, and the dot changed its placement on the ruler. When I moved my head left, the dot also moved left; so that when the dot was at the left border of the reticle, it was approximately 1" left of the original POA. When I moved right until the dot was at the border, the dot was about 1" right of the original POA. That's why I said originally that the shot would stay within a 2" circle --- if I can still see the dot, even at the border of the reticle, it's off by 1" at most.

My EOTech never changes the dot position no matter where my head and eyes are. If my EOTech circle/dot are on something, I can move my eyes anywhere, and the dot always stays on one spot. So it has basically no parallax.

That's whats bothering me about this Aimpoint 2x. I can't figure out if the parallax is supposed to be like this because of the magnification, or if my unit is defective. Thanks for the links to the AR Forums --- I probably would have thought again about the 2x if I had read those threads. My reasoning was that a .308 carbine would be more flexible with a magnified optic.

I haven't found anything directly on point to explain why a magnified optic produces parallax, but I'm thinking that magnification = parallax. The only hint was the spec on the Leupold Mark 4 red dot, which is a 1-3 variable. The Leupold stat sheet says that its parallax is adjusted for 150 feet. By this theory, parallax may be noticeable at close ranges, but should be zero or miniscule at the factory adjusted range.

As a follow-up, I just put my 2x on a stable surface and did the same procedure with a wall about 35-40 feet away. The dot only moved about 1/2" in each direction, giving me a 1" circle if I can see the dot.

I suspect that at longer distances, parallax should be almost zero. I think that it has something to do with magnification, focal planes, and long/unlimited eye relief -- which is beyond me. Frankly, I'm not unhappy with the M2 2x, but it does have limitations. Even without having it mounted, I can tell that it'll be hard to use with both open. The FOV is not good. Maybe a return is in order.

 

[Chris Rhines]

Aimpoint M2's have NO parallax, none, NADA!

This is just not true. It is physically impossible to make a red-dot sight that is parallax-free, at least by the traditional diode-and-tube methods. http://ourworld.compuserve.com/homepages/Dreyer_infonet/dotsight.htm

- Chris