Explanation of Co-Witness

[DocGKR]

I zero my irons first.

Then I zero my optic.

When using my preferred red-dot optics (Aimpoints in LaRue mounts) in every case to date, the red-dot has been perfectly centered on the iron sight front post tip when looking through the irons and optic simultaneously. In other words, my irons and red-dot have the same POA/POI and are CO-WITNESSED.

If my red-dot and BIS have been co-witnessed during the initial zero, then at the beginning of each shift/operation I can flip-up the BIS and ensure the red dot is co-witnessed as a quick verification that my zero has not shifted. Then I flip-down the BIS and go about my business. In my world, that is the main benefit of co-witness.

[C4IGrant]

I zero my irons first.

Then I zero my optic.

When using my preferred red-dot optics (Aimpoints in LaRue mounts) in every case to date, the red-dot has been perfectly centered on the iron sight front post tip when looking through the irons and optic simultaneously. In other words, my irons and red-dot have the same POA/POI and are CO-WITNESSED.

If my red-dot and BIS have been co-witnessed during the initial zero, then at the beginning of each shift/operation I can flip-up the BIS and ensure the red dot is co-witnessed as a quick verification that my zero has not shifted. Then I flip-down the BIS and go about my business. In my world, that is the main benefit of co-witness.

This is how I do it as well.


There seems to be a lot of debate as to whether an "absolute" co-witness (as Dick S. used to call it) is the preferred version of the co-witness.

Most of us I think prefer a bottom 1/3 co-witness simply for the reason that it keeps more of your irons out of your FOV. I think people sometimes forget that the optic is the PRIMARY sighting system and the irons are the secondary.

To make it even more interesting, I have even seen some Tier 1 weapons that did NOT co-witness at all (on purpose). The thought was that an optic that is mounted up higher allows for ones head to be more upright giving better Situational Awareness. If the optic goes down, the operator can still point shoot until he can remove the optic and go to the irons.

I have been practicing this recently, by removing my optic and just using my front sight base (no rear) to shoot human size targets out to 75yds! It is VERY easy to do and am fairly confident that I could keep someones head down at much longer distances.


C4

[DrMark]

...so after this thread, I'm picturing a Vodka ad: Absolut Co-Witness

Too bad I have no Photoshop skills.

[2011BLDR]

An optic that is mounted up higher allows for ones head to be more upright giving superior performance in the following areas:
Better Situational Awareness
Less helmet shift that interferes with vision and sighting
Less neck strain from having the helmet and NVG’s tilted off center
Overall better balance and smother movement

Optics are the primary and in some unit’s the 2nd back up. If the primary is a 1.?-4X of some kind (TR21, Short Dot, NF…) the CQB dot (M68, EoTec, MRD) is the secondary and the Irons are the last resort . If the optic goes down, the operator can still shoot using the window, silhouette of the optic or a top adjustment knob as a reference point to aide in alignment until he can remove the optic and go to a secondary optic before being reduced to the irons.

The advantage of the optic is in reducing the number of things in the sight picture down to 2 ( retical & Target) from 3 ( Rear sight , Front sight & target). The “absolute co witness “ is a step back wards as you now have 4 things in the sight picture (Rear sight , Front sight retical & target).

Out,
2011BLDR

[Mojo58]

...so after this thread, I'm picturing a Vodka ad: Absolut Co-Witness

Too bad I have no Photoshop skills.

LOL

[SinnFéinM1911]

Co-witness = seeing two at the same time, regardless of plane.. equal to or bottom 1/3. The key point is being able to rapidly shift to irons in the unlikely event your optic fails.

An EoTech on a riser will put the irons below the red dot, many Aimpoint mounts do this by design. You then have to zero Irons & Red Dots seperately.

Many folks get lazy and just zero the dot & move the Irons to it.... or vice versa. The validity of this zero depends on the plane of the optic/dot and the irons. Best to zero one then the other seperately.

I have also heard as it as:

A ability to quickly sight in your Iron after your Optics / Red Dots BZO'd, and adjsut your iron sights or buis to that point (seems kinda lazy to me).

[Robb Jensen]

I have also heard as it as:

A ability to quickly sight in your Iron after your Optics / Red Dots BZO'd, and adjsut your iron sights or buis to that point (seems kinda lazy to me).

Very lazy. I think they should be sighted in independently so you'll know each works on it's own.

[Wayne Dobbs]

I think that however it's ultimately defined, co-witnessing does involve being able to see and use both systems at the same time.

As an alternative and to put a Pat Rogers spin on it, "...co-witnessing is watching TWO hot chicks get it on...."

[SinnFéinM1911]

I guess this is what I am saying. and I think everyone here has shown that there is NO true ONE definition to a "Textbook" or Doctrine to a actual Co-Witness. Its amazing to me that a term that is so widely used and thrown around as "must have" when buying optics and BUIS is a true unknown.

[combatvet]

In my Arm chair commando opinion:

The only right way to do this is to first sight in your BUIS(s) and then "co-witness" your dot/scope/whatever.

That way if you ever have an optic failure you know for certain your BUIS(s) are calibrated for POA.