PDA

View Full Version : How do you prefer your co-witness?



adrenaline151
2 March 2009, 13:47
Using an Eotech or Aimpoint, do you like to have the irons centered or in the bottom 1/3 of the optic? Does it make a difference for your cheek-stock contact?

John Hwang
2 March 2009, 14:49
I personally like lower 1/3 cowitness which will allow your head to be in a more natural upright position for faster target acquisition.

Stickman
2 March 2009, 16:08
I prefer a real cowitness, but shoot fine with either. A real cowitness allows me to check my BUIS and optic are still dialed in, which is nice if I haven't had a chance to shoot my duty weapon in awhile. If I find that things have moved, I know I've got an issue.

m24shooter
2 March 2009, 16:12
I prefer a real cowitness, but shoot fine with either. A real cowitness allows me to check my BUIS and optic are still dialed in, which is nice if I haven't had a chance to shoot my duty weapon in awhile. If I find that things have moved, I know I've got an issue.
Same here. I like looking through the sights and seeing one aim point.

John Hwang
2 March 2009, 16:51
You can still check to see if your red dot and irons are dialed in on bottom 1/3 co-witness as well.

The whole point of having a red dot like an Eotech or Aimpoint is not having to look down your sights. Point and shoot...
For me, I drop my head and co-witness if I am doing precision shooting. Other than that, I point the red dot and shoot.

Cameron
2 March 2009, 17:17
John is right, with a paralallex free red dot you can confirm co-witness if it is 1/3 or absolute.

I like 1/3 when I have a fixed front sight post, and a absolute co-witness when I have flip up BUIS.

Here is the 1/3 on a 14.5 with fixed front post, I use the LaRue EOTech riser to get the FSP in the lower 1/3.
http://i496.photobucket.com/albums/rr323/cforumsemail/Misc/1third.jpg


Here is the absolute co-witness on a 16" with a PRI flip up front sight, EOTech is bolted right to the receiver.
http://i496.photobucket.com/albums/rr323/cforumsemail/Misc/absolute.jpg


Painted rifle has 1/3 due to riser, black rifle has absolute co-witness but is run with the BUIS folded out of sight.
http://i496.photobucket.com/albums/rr323/cforumsemail/Guns/145and16inch2.jpg

adrenaline151
2 March 2009, 19:11
so on an eotech, does the 1/3 thing apply, I mean, wherever the dot it is, is where the bullet will hit, right? If your sights are on, and your eotech is on, it's just a matter of where you look... at the sights or over them, right? Does that make sense? The height of the eotech and your head position would make it center or lower 1/3 co...right?? (Please forgive me for guessing, I've never used an eotech to shoot, just looked at one on a rifle).

Paulo_Santos
2 March 2009, 19:15
If it has a fixed front sight, I like the lower 1/3. If it has flip-ups, I don't care.

Eric
3 March 2009, 01:01
I started out with a true co-witness years ago and find it more comfortable for me. Perhaps due to that primacy learning thing we all hear about. With that said, I do have some mounts that utilize the lower third for the irons.

Stickman
3 March 2009, 09:59
so on an eotech, does the 1/3 thing apply, I mean, wherever the dot it is, is where the bullet will hit, right? If your sights are on, and your eotech is on, it's just a matter of where you look... at the sights or over them, right? Does that make sense?



You are correct, the bullet is going to hit where ever you have the dot on the target when using the eotech.

durangojim
3 March 2009, 12:12
so on an eotech, does the 1/3 thing apply, I mean, wherever the dot it is, is where the bullet will hit, right? If your sights are on, and your eotech is on, it's just a matter of where you look... at the sights or over them, right? Does that make sense? The height of the eotech and your head position would make it center or lower 1/3 co...right?? (Please forgive me for guessing, I've never used an eotech to shoot, just looked at one on a rifle).

I have an eotech on a riser that gives me a lower 1/3 cowitness. What I like about it is if my head is up, I'm not looking throught the irons. If I move my head down, then I have an absolute cowitness. I'm not LEO or military so I can't comment in advantages/disadvantages in tactical situations.

TehLlama
3 March 2009, 16:15
I'm all absolute cowitness - I tend to position my head low even for that, so it works best for me. I can fully understand why lower 1/3 would work best for most folks still.

:ETA: This is the setup I'm running on my Lightweight, and my wife's carbine. I think you'll really like it for that use.

rob_s
12 March 2009, 02:34
I've come to like fixed front and rear with the fullsize Aimpoints, and so like a lower 1/3 to keep the sight picture uncluttered.

One thing I want to play with a bit more is an Aimpoint Micro set at "absolute" cowitness with a flipup rear sight. My theory is that I'll never notice the front sight until I need to and when I want to use it, the micro will act as more of a rear ghost ring.

patriot1988
13 February 2010, 10:14
You are correct, the bullet is going to hit where ever you have the dot on the target when using the eotech.

Will this work with an Aimpoint M2?

scumhunter
14 February 2010, 01:12
Yes, it is the same with an Aimpoint.

I am a true co-witness guy as well. I like to be able to confirm my optic is locked on in case I need to take a precision head shot in a hostage or other tight situation (keeping in mind my 2" hold-over for close encounters). When doing entry work I don't even see the iron sights. I had a lower 1/3 co-witness for a long time but I bought a new mount to switch over to a true co-wit.

devilpig
14 February 2010, 01:25
I prefer a lower 1/3.

Aligning with several points already mentioned I'll explain.

An absolute co-witness doesn't necessarily bother me, but I feel like there's just too much going on. Granted it comes down to training, but for me I don't want to be thinking about aligning irons as well as looking for a reticle. It's just too much in my opinion.

With my T-1 and no parallax I can still confirm that nothing has moved by looking through the irons. But for speed I'm just going for the dot.

For flip-up sights it wouldn't make as big of a difference to me as the irons would be out of the way most of the time.

I don't think there is a RIGHT way to approach this, it's all personal preference and training.

Fontaine
16 February 2010, 13:29
My face is skinny and bony, and I can't get a good cheek weld with lower 1/3 co-witness. It's more of a chin/jaw weld for me.

For those reason, personally, I prefer an absolute co-witness.

scumhunter
17 February 2010, 07:19
My face is skinny and bony, and I can't get a good cheek weld with lower 1/3 co-witness. It's more of a chin/jaw weld for me.

For those reason, personally, I prefer an absolute co-witness.

I would suggest a daily box of tactical twinkies until your cheek weld is operational. [pop]

pezboy
17 February 2010, 11:47
I prefer absolute co-witness. I use a flip up rear or front and rear, so there isn't any issue of the irons being in the way. I also like to have all of my rifles set up so that the optic height and eye relief (if applicable) are all the same so that my cheek weld is consistent. If I use a rifle with an ACOG my head is in the same position as if I use a rifle with an Aimpoint, and so on.
Dustin

Captains1911
18 February 2010, 06:00
For me, I prefer an absolute co-witness with an EOTech but a lower 1/3 with Aimpoint. If I had to pick one to use for both I would choose lower 1/3.

Model6520
20 April 2010, 22:32
I'm mounting an Aimpoint on an A2 forward of the carry handle on an ARMS SIR #51, and am trying to decide on absolute co-witness vs. lower 1/3.

If I were usint a flat-top with flip-up rear sight, I'd definitely go with absolute co-witness. However, with the fixed carryhandle/rear sight of the A2, it seems like the lower portion of the Aimpoint's sight picture might be somewhat obscured by the rear sight/carry handle.

Thanks in advance for your thoughts!

Kitty
21 April 2010, 00:03
A little off topic but the verification of consistency between the optic and the irons should be part of your daily inspection ritual, especially if you 'really' use your gun.

I always do that, and I did it once and found that the dot of my optic, which is always right on top of the front sight post, was sitting at the bottom. My optic was off by 40 clicks. The issue was resolved but it's obviously very good that I caught it.

Kitty
21 April 2010, 00:10
Also, in response to the original question, I use absolute cowitness with flip up front and rear BUIS. The difference in sight offset between absolute and lower cowitnessed optics might be negligible, but it is slightly different, which theoretically would force a different cheek weld when using an optic vs. irons. Also, the minute difference in sight offset could (but probably wouldn't) create confusion in the use of close cover and result in shooting the cover by mistake because of the increased offset.

My personal preference is not to use a fixed front sight, simply because the view through the optic is less obstructed allowing you to see critical things which could be occurring in the obscured area. It's a small point and I know lots of people who feel the permanence of a fixed front sight (especially in the case of an optic failure) outweighs the open field of view, and it all boils down to personal choice.

Quib
21 April 2010, 03:25
A little off topic but the verification of consistency between the optic and the irons should be part of your daily inspection ritual, especially if you 'really' use your gun.

I always do that, and I did it once and found that the dot of my optic, which is always right on top of the front sight post, was sitting at the bottom. My optic was off by 40 clicks. The issue was resolved but it's obviously very good that I caught it.

Type of optic used?

Any idea what could have thrown your zero that far off?

Rated21R
21 April 2010, 05:15
absolute co-witness. i got used to lollipopping on my duty rifle. my build has flip-ups but i still went with an absolute co-witness Bobro setup.

John Hwang
21 April 2010, 09:06
I'm a lower 1/3 person myself. This allows me to keep my head in a more natural upright position for quicker target acquisition and then I can drop my head slightly and use my irons and dot for a longer precision shot.

Kitty
21 April 2010, 11:19
Type of optic used?

Any idea what could have thrown your zero that far off?

Aimpoint in a cantilever mount....the best the range staff could figure was we hit a speed bump or something going too fast and the rifle slammed into something in the truck which knocked the optic out of alignment. Which should NOT happen...you should be able to chuck your rifle across a parking lot or drag it behind your car for a few miles and have it still work...

Quib
21 April 2010, 12:08
Aimpoint in a cantilever mount....the best the range staff could figure was we hit a speed bump or something going too fast and the rifle slammed into something in the truck which knocked the optic out of alignment. Which should NOT happen...you should be able to chuck your rifle across a parking lot or drag it behind your car for a few miles and have it still work...

Interesting......thanks Kitty, and welcome to Weapon Evolution. [:)]

Some of those cantilever mounts seem to stretch out there pretty far forward. I wonder if the impact to your weapon slightly bent the mount?

Jerry R
21 April 2010, 16:49
I prefer lower third - only because that is what I shot before making my current purchase, and that is what I have. Dot on the post seems to make me take more (spell that "too much") time on the shot. Longer I hold, shakier I get [BD] and I end up chasing the dot.

So, I put an EOTech 516 on the carbine because it has a built-in 7mm riser. I really like it.

That was the answer, now for the question.

Today I ordered a new flat-top toy.

Along with it, I ordered an EOTech XPS2-0 and Second Generation G23.FTS 3x Magnifier. Selection based on rail real estate and weight. How can I mount them both for a lower third witness?

Most QD picatinny mounts (ringless) or risers are 5/8s high rails instead of .275 or 7mm. That puts the irons out of view. So my choices seem to be - I can FTS the 3x and use the irons in true witness, or remove the EO and just use the irons in a dead dot scenario. Both seem less than ideal to me.

Wait one, I'm thinking through that last comment [crazy] dead dot means no witness, just look through at the irons stupid! Sorry I got side-tracked. With the dot working, I still think I prefer lower third.

Don't want to hi-jack the thread, but your responses may help others also. [adore]

Quib
21 April 2010, 18:01
I prefer the “lower 1/3rd” co-witness.

For some reason I have trouble with crowded FOV’s and focusing on the target. The less clutter in my FOV, the better.

Kitty
23 April 2010, 00:17
Interesting......thanks Kitty, and welcome to Weapon Evolution. [:)]

Some of those cantilever mounts seem to stretch out there pretty far forward. I wonder if the impact to your weapon slightly bent the mount?

That was the theory, although it did not appear bent (but an offset like that, although extreme in point of impact, would be very small in degrees)...and it should NOT happen. But, something did. Nobody's been able to say for sure. The mount I was using is a very popular, very well known and regarded mount that nobody else has had the same problem with, so I tend to think it was user error of some sort. But I still don't know what...

Quib
23 April 2010, 03:28
That was the theory, although it did not appear bent (but an offset like that, although extreme in point of impact, would be very small in degrees)...

Even though the offset at the point of impact may have seemed minimal, you have to take into account that as distance increases along the line of sight, so does that offset caused by the impact. So a degree or two of deflection in the actual mount, gets amplified the farther out your POA is.

Anyway, interesting story, thanks for sharing, and again welcome to Weapon Evolution. [:)]

yxl2
24 April 2010, 06:03
Lower 1/3 and nothing higher.

Deaj
17 May 2010, 07:16
I prefer a real cowitness, but shoot fine with either. A real cowitness allows me to check my BUIS and optic are still dialed in, which is nice if I haven't had a chance to shoot my duty weapon in awhile. If I find that things have moved, I know I've got an issue.

This. I'm running an Eotech and flip-up BUIS.

AR-10
26 July 2010, 13:02
I read this entire thread (and many others on different forums) and I still can't decide which ADM mount to order for my T-1.

I have experience with flip-up front and rear sights and absolute co-witness but I've never seen the same setup with a fixed front.

I think I would prefer to have the front sight out of the way, but I like the idea of maintaining the same cheekweld for the dot and irons.

This is why it takes me months to finish one rifle, I can never make up my mind on anything.

Wondering Beard
26 July 2010, 13:55
You can still check to see if your red dot and irons are dialed in on bottom 1/3 co-witness as well.



How exactly do you do that?

Paulo_Santos
26 July 2010, 14:02
I read this entire thread (and many others on different forums) and I still can't decide which ADM mount to order for my T-1.

I have experience with flip-up front and rear sights and absolute co-witness but I've never seen the same setup with a fixed front.

I think I would prefer to have the front sight out of the way, but I like the idea of maintaining the same cheekweld for the dot and irons.

This is why it takes me months to finish one rifle, I can never make up my mind on anything.

You can write a book about co-witness. First, you need to decide if you want front and rear flip ups or if you want a fixed front and rear flip-up, or if you want fixed front and rear. From my experience, it gets annoying when I had a fixed front sight and a co-witnessed red dot and/or when I had a 1x4 scope with a fixed front sight. For some people it isn't a big deal, it was annoying to me.

If I have a choice, I'd prefer front and rear flip-ups. They are more versatile and you can always leave them in the up position if you want to.

Then there is the problem with the sight height. A regular BUIS or Iron sight is just under 2.6". Most co-witness mounts are actually 2.75" tall and the lower 1/3 co-witness are close to 3'. You often hear people say that the lower 1/3 co-witness is the best because it keeps your head in the upright position, which is ideal for CQB. The problem is that not everyone is 6'03" tall. I tried a couple of the lower 1/3 co-witness mounts and it was so high for me that I had a chiweld position. So I would recommend that you check your iron sights and see where your head position is. If you look through your iron sights and your head is already upright, then you should probably use a regular co-witness mount. If you look through your irons and your head is leaning over, then you may want to use a lower 1/3 co-witness mount.

Paulo_Santos
26 July 2010, 14:03
How exactly do you do that?

Just look through your irons and the dot will move and should be lined up with the irons.

AR-10
26 July 2010, 14:21
So I would recommend that you check your iron sights and see where your head position is. If you look through your iron sights and your head is already upright, then you should probably use a regular co-witness mount. If you look through your irons and your head is leaning over, then you may want to use a lower 1/3 co-witness mount.

This is by far the best advice I have read on this subject.

I already have a fixed front sight on this particular upper, and I do indeed drop my head just to look at my irons so I think I'm going with a lower 1/3 mount.