Absolute or lower 1/3 cowitness mount list?

[USNsheepdog]

First off, I'd like to apologize if there is already a thread for this but I've been searching for quite a while now and haven't been able to find it.

I'm trying to find a list of Aimpoint mounts that states whether the mount is absolute or lower 1/3 cowitness. Every website I've been on just says the mount provides a cowitness with BUIS. Some tell you how high the mount puts the centerline of the optic above the rail, but I can't find the relationship of those measurements to the type of cowitness. It's a bit frusrating to have to either call the company or look around to find out which type of cowitness the mount provides. I think it's a pretty vital bit of information to include when you're trying to sell a product, but that's just me... Any input is appreciated!

Thanks,
Gary

[Singlestack Wonder]

Here's a couple of 1/3 lower co-witness mounts for 30mm Aimpoints:

http://www.americandefensemanufacturing.com/view/product/3/

http://stores.homestead.com/Laruetactical/Detail.bok?no=26

Here's a Chart from LaRue Tactical showing various mounts with illustrations for Micro Aimpoints (H1 & T1)

http://www.laruetactical.com/pics/LT66XMount/Micro_Chart.jpg

[USNsheepdog]

Here's a Chart from LaRue Tactical showing various mounts with illustrations for Micro Aimpoints (H1 & T1)

http://www.laruetactical.com/pics/LT66XMount/Micro_Chart.jpg

That's helps a bit. The cantilever mounts for the M series Aimpoints are the ones I couldn't find cowitness info about.

MI#15 (I really like this one)
http://www.midwestindustriesinc.com/index.cfm?fuseaction=category.display&category_id=83

LT129
http://stores.homestead.com/Laruetactical/Detail.bok?no=37

Neither of these state whether it's absolute or lower 1/3 cowitness.

[Singlestack Wonder]

That's helps a bit. The cantilever mounts for the M series Aimpoints are the ones I couldn't find cowitness info about.

MI#15 (I really like this one)
http://www.midwestindustriesinc.com/index.cfm?fuseaction=category.display&category_id=83

LT129
http://stores.homestead.com/Laruetactical/Detail.bok?no=37

Neither of these state whether it's absolute or lower 1/3 cowitness.

The LT129 positions the center of the optic 1.7" from the top of the rail the same as the LT150.

[USNsheepdog]

The LT129 positions the center of the optic 1.7" from the top of the rail the same as the LT150.

Would that mean it's absolute or lower 1/3 cowitness?

[Singlestack Wonder]

1/3rd Lower co-witness.

[Crow Hunter]

From my "research" absolute will give you approximately 1.5" above the rail to the center of the optic and a lower 1/3 will give you approximately 1.75" above the rail. There is some difference between manufacturers but this is the Larue "standard".

If you are trying to decide, you really should try both out. I have both and the "absolute height" is not as comfortable or natural for me unless I am laying prone behind the optic. The Larue 1.75" height is ideal for me when I am up on 2 legs and or moving around, but it is a little high in prone.

Hopefully I didn't confuse the issue too much.:D

[ra2bach]

what optic are you asking about?

[BCmJUnKie]

If youre goin with Aimpoint, get the LaRue STANDARD mount. Its bottom 1/3. There is no benefit to absolute co-witness. If you dont have the optic yet, go to Larue, they have Optic/Mount combo's that save you almost $100 bucks. I picked my CompM3 up w/mount for I think 650

[HeavyDuty]

There is no benefit to absolute co-witness.

Opinion does not equal fact.

Gary, I prefer absolute cowitness so have a limited choice of mounts to pick from. I ended up with a couple of ADM AD-68s for M3-type sights. They have three heights - no suffix = absolute, H = lower 1/3 and L = low mount for things that need it.

[BCmJUnKie]

Opinion does not equal fact.

And neither does personal preference. What benefit is there? POA/POI is still exactly the same.

[Singlestack Wonder]

I prefer 1/3rd lower co-witness. For long range shots, not having the FSB touching the bottom of the red dot allows for a better sight picture as well as offering holdover viewing of the target.

[BCmJUnKie]

I prefer 1/3rd lower co-witness. For long range shots, not having the FSB touching the bottom of the red dot allows for a better sight picture as well as offering holdover viewing of the target.

Thats what I like too. I recently went with a Comp M3. But I still use my Eotech also. I like both

[boomhower]

I prefer lower 1/3. I went with an AMD standard, non-cantilever mount and love it. If you qualify for LEO/.mil discounts you can get a killer deal for them at dsgarms.

[Schadenfreude]

If you are using an aimpoint or eotech the main advantage is that it doesn't matter where in the window the dot is - only if. You leave the rear sight up should the dot be locked to the top of the post - I prefer absolute with fold down front & rear this gives you the instant ability to do a rough zero check without firing a shot if you think one or the other has been knocked off of zero. Also if you have a red dot sight with a front cover you can shoot with both eyes open while leaving the front cover closed on the sight & still hit perfectly so the front sight in the way will be irrelevant.

If you have an astigmatism & your dot looks blurry use it with the rear sight absolute & it will remove the blur

[HeavyDuty]

And neither does personal preference. What benefit is there? POA/POI is still exactly the same.

The benefit to me is seeing more of the front sight base. You may prefer a different setup, but don't assume your preference is the only way to do it.

[BCmJUnKie]

The benefit to me is seeing more of the front sight base. You may prefer a different setup, but don't assume your preference is the only way to do it.

I never did. And I dont assume. Ever. If I dont know then I ask. I was stating....what are the BENEFITS of having an ABSOLUTE co witness. My Eotech has an absolute co witness, my Aimpoint dont, My preference is not bias.

[Crow Hunter]

If you are using an aimpoint or eotech the main advantage is that it doesn't matter where in the window the dot is - only if. You leave the rear sight up should the dot be locked to the top of the post - I prefer absolute with fold down front & rear this gives you the instant ability to do a rough zero check without firing a shot if you think one or the other has been knocked off of zero. Also if you have a red dot sight with a front cover you can shoot with both eyes open while leaving the front cover closed on the sight & still hit perfectly so the front sight in the way will be irrelevant.

If you have an astigmatism & your dot looks blurry use it with the rear sight absolute & it will remove the blur

That's not really true.

1. Inside of 50 yards, it DOES make a difference where the dot is in the tube. You do get "some" parallax. Outside of 50 yards, you are "parallax free". (You can try this for yourself at home. Put the sight in a vice, put the dot on something in your living room and change your head position. It won't stay on the same point at close range.)

2. You don't have to have absolute to check zero. All you need to do is aim at your target with your (something more than 50 yards away;)) with your sights and your dot should be right on top of your front sight, assuming you use a 6:00 hold.

3. You should ALWAYS shoot with both eyes open with a RDS. Otherwise you are going to be sighting down a very narrow tube and occluding your other eyes view of the target and greatly restricting your situational awareness..

4. It won't hit in exactly the same point with the cover up. It can't. Your non-domninant eye is over some difference laterally (unless you are very deformed:p) and it will be offset towards the eye that isn't looking through the occluded sight.

5. You're right about the astigmatism though.:D

[montrala]

Can, by the way, someone tell me what are actual heights (from rail to base of RDS or from rail to centre of tube) of LT-660HK and LT-751 mounts?

[rob_s]

I use both absolute and 1/3. I find the statements of opinion as fact in this thread downright comical.

To the OP...

That MI mount looks INSANELY expensive for what it is. MI, to my mind, typically offers cost savings as one of the reasons to opt for them but there is no way I would pay MORE for a thumscrew mount than a throwlever mount from one of the other manufacturers.

I've always intended to catalog the various mounts into a chart but just have never gotten around to it. Obviously the mount height information is something I would want to include, and like you I find it odd that so many manufacturers don't include it. I'd like to see them state the actual centerline height above rail rather than simply saying "absolute" or "lower 1/3".

[markm]

If youre goin with Aimpoint, get the LaRue STANDARD mount. Its bottom 1/3. There is no benefit to absolute co-witness.

I somewhat agree. I mean... if you have to snap the gun up to your cheek for a full cheek weld...might as well use the superior iron sighting system.

Lower 1/3 isn't perfect either though.. you have this honkin' electronic sitting even taller on your gun which is a little bulkier and clutters up your down range vision... plus shooting irons with a lower 1/3 optic just flat sucks... I screws up your sight picture.

[R Moran]

FWIW,
A friend has an MI, and told me its an absolute co-witness.

I've tried/used the the Warne Aimpoint specific ultra high ring, it is absolute co-witness.
I've tried/used the "Gun-tech" Brownells brand, absolute-co-witness also. I would almost swear it was offset to the right also.

Bob

[Schadenfreude]

That's not really true.

1. Inside of 50 yards, it DOES make a difference where the dot is in the tube. You do get "some" parallax. Outside of 50 yards, you are "parallax free". (You can try this for yourself at home. Put the sight in a vice, put the dot on something in your living room and change your head position. It won't stay on the same point at close range.)

2. You don't have to have absolute to check zero. All you need to do is aim at your target with your (something more than 50 yards away;)) with your sights and your dot should be right on top of your front sight, assuming you use a 6:00 hold.

3. You should ALWAYS shoot with both eyes open with a RDS. Otherwise you are going to be sighting down a very narrow tube and occluding your other eyes view of the target and greatly restricting your situational awareness..

4. It won't hit in exactly the same point with the cover up. It can't. Your non-domninant eye is over some difference laterally (unless you are very deformed:p) and it will be offset towards the eye that isn't looking through the occluded sight.

5. You're right about the astigmatism though.:D


1. Ok there is some parallax at close range imo practically zero. All my rd's stay within 1" at roughly 3 yrds no matter where they are in the optic, in a cqb situation .5" at 3yrds shouldnt matter unless your doing something that you probably don't have time to do anyway.

2. I have what I call absolute zero & my dot is split by the top of the front sight at range when looking through the sights. I zero my sights to split the center of a bullseye. I zero my dot to sit on the center of a bullseye thats my personal preference. You are correct 1/3 or absolute should look the same at range as far this relationship of irons to dot goes.

3. I do shoot with both eyes open I was just trying to show a point about the front sight.

4. Ive never had trouble ringing 6" steel at 200 yrds with the cover closed (as an experiment) so if it is of it isn't by much.

[Schadenfreude]

"There is no benefit to absolute co-witness."

If there is no benefit what is the downside?

[kmrtnsn]

A cluttered sight picture.


---
I am here: http://maps.google.com/maps?ll=34.276165,-118.378733

[Schadenfreude]

That is why use front & rear flip up sights - hence no clutter, also no need to find 2 seperate cheek welds.

[Schadenfreude]

To the OP some mounts are mentioned by name in this thread

https://www.m4carbine.net/showthread.php?t=17049

[Failure2Stop]

That is why use front & rear flip up sights - hence no clutter, also no need to find 2 seperate cheek welds.

Hence no irons for immediate use when the RDS goes down.

Really though, this has been chased around the tree many times.
There are very few shooters with what I consider significant experience on both arraingements that opt to employ absolute cowitness.
Neither side seems to give up their (usually random by virtue of purchase) preference with anything but time on gun and with side by side testing.

Really though, this thread was started to ask about mount heights, so further dialogue should at least contain a reference to a mount and whether it is absolute or lower 1/3 cowitness and/or your experience with that mount.

Thanks.