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jdberger
02-09-2006, 11:47 PM
Can someone give me the skinny on co-witnessing iron sights with optics?

Seems to be all the rage these days.

BigAL
02-10-2006, 5:46 AM
Taken from the Maryland AR-15 site.

Q: What is 'Co-Witness'? And, how is it good?

A: Co-Witness is the ability of your irons to look through your optic (1x - not magnified) - so they both shoot on the same trajectory. There are two kinds - absolute (both the dot and irons are on the same plan), and offset (where the irons are usually in the lower 1/3 of the optics display). With co-witnessed sights you can verify the zero of the optic by looking through the irons (the dot should sit on top of the front sight). However, normally you look over the irons and just use the optic (trust me, you won't notice the iron sights); should the batteries fail your head comes down a fraction of an inch and you're using the iron sights (looking throught the now-dead optic).

Below: This diagram from Onslaught of AR15.com demonstrates the principal of 'Co-Witness' perfectly. The top images show what the sight picture looks like when you look through the irons - the lower picture shows what the sight picture is normally like.

http://groups.msn.com/isapi/fetch.dll?action=MyPhotos_GetPubPhoto&PhotoID=nJwAAANwMUuAJ7JC8BIu3u5hfwsqH9Z0x3oIwsknAV fVqkoJ0B820UgDvJdctqwwGbFtqpVZEnbk


I run a lower 1/3 co-witness with my Larue cantilever Aimpoint mount to try to see less of the front sight when looking through the optic.

ETA: Another good thing about having your dot line up with the top of your front sight post when looking through the rear BUIS is that it gives you a quick check that your optic is still holding zero and has not shifted. If you are installing your optic on a rifle that already has a zeroed BUIS you can adjust the dot so it is on top of the sight post before you ever hit the range. Then it's just fine tuning it once you get there.

Fjold
02-10-2006, 7:04 AM
I have my 375 H&H magnum set up with Talley quick release rings and a 1x4 Leupold scope. At 1X the blade of my front sight is almost 1/3 of the way up in the scope's field of view. At 4X you don't even see it.

jdberger
02-10-2006, 7:46 AM
I have my 375 H&H magnum set up with Talley quick release rings and a 1x4 Leupold scope. At 1X the blade of my front sight is almost 1/3 of the way up in the scope's field of view. At 4X you don't even see it.
Do you use that for CQB?

[I almost pee myself i'm so funny]

50 Freak
02-10-2006, 9:07 AM
Only against Rapters and small T-Rexs.

stevie
02-10-2006, 9:13 AM
Jeez, maybe big T-Rexs....

stevie
02-10-2006, 9:14 AM
or is that the 50 BMG with AP's for big T-Rex's, ;)

Fjold
02-10-2006, 9:28 AM
[QUOTE=jdberger]Do you use that for CQB?



I use the scope for long range work but go to the open sights when I have to go into the brush to put down a wounded saber toothed ground squirrel.

jdberger
02-10-2006, 9:14 PM
the most dangerous game

http://www.worth1000.com/entries/125500/125826XeGD_w.jpg

C.G.
02-11-2006, 12:48 AM
the most dangerous game

http://www.worth1000.com/entries/125500/125826XeGD_w.jpg

:eek: :eek: :eek: !

LOW2000
02-11-2006, 9:27 AM
From http://www.rbprecision.com/rb_precision_ar15_performance_tips_.htm

The site is full of pictures of the items. Good prices on stuff too if you email them.

Co Witnessing (what will and WILL NOT work) More pics to follow!




Rock River Tactical carry handle (on an A4 Flattop Receiver)

An EOtech will not co witness when sitting on the RRA Tactical Carry Handle.
An Aimpoint (ML series) will co-witness when using a Low and Wide X-ring mount.
An A.R.M.S. #22M68 quick disconnect throw lever will attach to this rail, there are spacers available but you will most likely use this without a spacer. This will co witness but the iron sights will be LOW in the sight picture, I do not recommend this.

A Aimpoint Rail Grabber will attach but WILL NOT co-witness.





Rock River Dominator Mount
This was developed to cowitness the built in rear sight with an EOtech, as far as I know nothing else will co witness.




A.R.M.S. 40's flip up rear (on an A4 Flattop Receiver)
Aimpoint ML series will co-witness with #22M68 and full spacer.
EOtech will co-witness.
Ziess Z point will co witness


ARMS #38 Sleeve (built in #40)
Will not cowitness with an EOtech
Will co-witness with Aimpoint with the X-Wide low ring


GG&G flip up rear (on an A4 Flattop Receiver)
Aimpoint ML series will co-witness with #22M68 and full spacer.
EOtech will co-witness. The irons will be low in the sight picture
Ziess Z point will co witness


Midwest Industries flip up rear (on an A4 Flattop Receiver)
Aimpoint ML series will co-witness with #22M68 and full spacer.
EOtech will co-witness. The irons will be low in the sight picture
Ziess Z point will co witness


Ziess Z point (on an A4 Flattop Receiver)
Will not co witness with a RRA tactical carry handle rear sight
Will co-witness with GG&G BUS
Will co-witness with ARMS #40
Will co-witness with Midwest Industries



ATN (American Technology Network...Ultra series 3, 4 or digital 5 reticle)
(on an A4 Flattop Receiver)

This inexpensive optic sits fairly high on a flattop, as far as I know the flip rears all sit too low to cowitness.



Hakko Panoramic (BED) 35 and BED 24

This inexpensive optic sits fairly high on a flattop, as far as I know the flip rears all sit too low to cowitness

Jicko
02-11-2006, 3:20 PM
LOW2000:

Thanks for the list.... can you update or can someone add whether it is 1/3 cowitness or full cowitness?

I want to find a 1/3 cowitness solution for my EOTech to be mounted on an A4 flattop.

LOW2000
02-11-2006, 8:12 PM
From what i've read, if you mount directly to the flattop, the iron sights will be dead on with the dot on the eotech. If you use a RRA dominator, the iron sights will be in the lower 1/3 of the sight picture.

Also, I got the petitions today, i'll try and get them filled and back asap. :D

jdberger
02-12-2006, 12:37 AM
From what i've read, if you mount directly to the flattop, the iron sights will be dead on with the dot on the eotech. If you use a RRA dominator, the iron sights will be in the lower 1/3 of the sight picture.

Also, I got the petitions today, i'll try and get them filled and back asap. :D

Thanks for the info and good luck with the RKBA petitions.:D

Jicko
02-12-2006, 7:45 AM
From what i've read, if you mount directly to the flattop, the iron sights will be dead on with the dot on the eotech. If you use a RRA dominator, the iron sights will be in the lower 1/3 of the sight picture.

Also, I got the petitions today, i'll try and get them filled and back asap. :D


So, as far as you know, if I want 1/3 co-witness with a EOTech, I've to get RRA Dominator? The Dominator is good, but it is ALWAYS there.... it would be nicer if it is ONLY BUIS, rather than always there....

Is there ANY flip-up/down sight that will do 1/3 co?

TonyM
02-12-2006, 8:34 AM
So, as far as you know, if I want 1/3 co-witness with a EOTech, I've to get RRA Dominator? The Dominator is good, but it is ALWAYS there.... it would be nicer if it is ONLY BUIS, rather than always there....

Is there ANY flip-up/down sight that will do 1/3 co?

Not a sight that I have seen, but there is the LaRue Tactical Eotech Mount. It raises the EoTech 0.275".

Many of the guys on AR15.com are building up with these instead of the "Dominator" which is an automatic loser in my book because of the fixed rear sight. I just went with flip up front and rear irons on my rifle I knew I was going to use the EoTech on, I like it much better than always having the FSB in the field of view..

Here's the URL for the Larue Mount @ LarueTactical.com
Larue Tactical Website (http://www.laruetactical.com/marketplace/servlet/Marketplaces?webEvent(ProductDetailAddPage,loadPro duct)&productID=1869&scrollTop=556)

Matt-man
02-12-2006, 9:45 AM
YHM also makes a riser for the EOTech. Neither the LaRue nor the YHM have a rear sight; just use the rear sight of your choice.

elmo
02-12-2006, 5:17 PM
i had the dominator and sold it because the rear sight is fixed.

right now just mount hte eotech directly on the flat top with a flip up rear. i'm happpy with how it is now.

Jicko
02-12-2006, 6:46 PM
Mind taking some rear sight pics and show us?

i had the dominator and sold it because the rear sight is fixed.

right now just mount hte eotech directly on the flat top with a flip up rear. i'm happpy with how it is now.

elmo
02-12-2006, 6:50 PM
Mind taking some rear sight pics and show us?

it's out of the way for me to do that now.

not that hard to imagine.

go to www.ar15.com click on the optics forum. there are tons of pics of recticles of aimpoint, eotech etc.

Jicko
02-13-2006, 9:07 PM
Flat-top + flip-up rear.... this is a 1/2 co-witness setup...

I just got in my flat-top, and i have a regular front sight.... I don't have a rear yet... but the front sight is kinda annoying in the front.... I think I need to get a riser for the EOTech.... maybe the YHM one.... pretty cheap...