How To Properly Co-Witness Optic With Iron Sight

Optics With Iron Sight

Nowadays, there are a lot of controversial topics in the shooting, hunting, and sports communities. They vary in both the focus and intensity of the discussion. One of these topics is the question of co-witness optics with iron sights.

Choosing the proper scope for your firearm is essential for accuracy, as it allows you to hit targets much longer distances than standard iron sights.

Regardless of the conditions in which you use scopes during the day, at dusk or night, or during competitions at the shooting range or hunting, you must quickly and accurately identify your target.

This is where scopes come in handy. Modern rifle scopes with high magnification, often designed as thermal or night vision scopes, allow you to perform various tasks.

With co-witness sights, you can make the process more efficient and accurate for every shot. You can ensure that the companies work optimally for your weapon with the right choice.

What is Co-Witness?

The problem that remains with “co-witnessing” red dots and irons is a classic combination of “overthinking it” and maybe a slight misnomer with the term “co-witness.”

To begin with, we need to understand what exactly does a co-witness mean?  The joint testimony concerns the relationship between the scope and the sights on your firearm. 

First, some think “alignment” implies that the screws must be aligned with the red dot for proper aiming.

You’ll be pleased to know that’s not the case – the last thing we’d want to do is give you yet another thing to have to “line up” before pulling the trigger.

Once zeroed at an appropriate distance and assuming we’re shooting at a distance within our firearm’s capabilities with that zero, all you need to do is put the red dot on the target where you want the bullet to go, pull the trigger without disrupting the gun’s point of aim, and that’s where the shot goes.

A front iron sight and a rear iron sight must be lined up properly to correctly aim the gun at the target, which requires consistent head/eye placement behind the rearview.

This is a “parallax error.” if you had the gun locked in place and moved your head/eye around behind the rear sight, you would see that it appears you are aiming at different spots on a target down range, depending on where your vision is located.

Red dots don’t have parallax error, so even as your head/eye are put in different positions behind the optic and the red dot inside the optic appears to be in other portions of the field of view, it’s always still aimed at the same spot down range.

This trips some people up and, again, causes them to want to go back to the old iron sights where they can visually see everything “lining up” before pulling the trigger. Trust the red dot – where it is over the target is where your bullet will go, assuming you’re all sighted in!

The gif we’ve created here shows this perfectly – even though the red dot appears to be moving around the field of view, it’s still hovering over the same spot on the target down range.

In addition, many gun owners facing the issue of a co-witness have many questions. Let’s look at a few of them.

“I heard I can sight in my iron sights, and then when I mount a red dot, just adjust the red dot to line up with those, and it’s all set.”

Again, these two completely different sighting systems work in two completely different ways. To confirm your zero with a red dot, shoot it without using the iron sights and fine-tune it as needed. That might get you close but never rely on this method for a zero.

“I heard using the red dot through the iron sights will mitigate my problems with a starbursting red dot from my astigmatism.”

Nine times out of 10 (OK, we didn’t do the math to get that number, but it’s a lot), the “starbursting” people are seeing with their red dot is not due to astigmatism at all, but rather a brightness level of the illuminated red dot that is too high for ambient lighting conditions.

Turning the brightness on the red drop-down often fixes this issue entirely and avoids any need to waste time lining up irons and a red dot. If you go that route, don’t even get the red dot in the first place because you’re robbing it of all its advantages in the first place!

Why perform a Co-Witness?

So, we have found out what a witness is and even considered several practical issues related to it, but the logical question remains: why do we need to do this at all?

It may seem that in this age of high technology, when optical and even night or thermal sights are pretty familiar and massively available on the market at affordable prices, it means that iron sights are an anachronism and a morally obsolete method of aiming.

However, this opinion must be corrected and reflect the state of affairs fully. After all, only some shooters always carry spare batteries or a battery pack for their scope to replace if the installed power supply runs out or breaks down for any reason.

Your optics may only succeed if you handle the weapon carelessly; for example, if it falls or you hunt in rough terrain, in the forest, or bushes, the sight may be damaged. And in the absence of a co-witness optic and iron sights, a severe problem arises because, in this case, it is impossible to shoot accurately and hit the target.

During hunting, such an event will mean that the game has escaped and you will not get the desired trophy, you will not win a prize at a sports competition, and you will simply spoil your mood even during training or target shooting for fun.

This means that it’s your insurance in case of emergency, so in such situations, you can continue shooting and not depend entirely on the technical condition of your scope.

How to implement a Co-Witness

So now that we have clarified what a co-witness is and why it is needed, a natural question arises: how to do it? Well, there are two main types of sights – absolute and 1/3.

These two options are best suited for different situations, also known as 100% co-witness and lower third. The main difference between these two types is the number of iron sights occupying your red dot’s reticle image.

With an absolute witness, you get 100% iron sights through your red dot. You see everything. The red dot or reticle of any type is located at the tip of the fly and is usually aligned with your sights.

With the bottom 1/3 of the navigator, you see the bottom third of your scope through the optic. A red dot will appear above the reticle when you look through the optic. If you lower your head down while using the reticles, the drop will move and appear above the reticles. 

Which option works best for you may depend on what you find most convenient and comfortable for your shot.
Let’s look at this issue on the example of one of the most popular weapons platforms, namely the AR-15:

AR-15 Absolute Co-Witness Sights

For AR-15 absolute co-witness sights, the optical sight mount is the same height as the iron sights. You have complete visibility of the iron sight through the optic because of the position of both parts.

You’ll be able to see the entire iron sight from top to bottom, and the optical sight will be at standard mounting height, in direct alignment with the iron sights.

With this setup, you have consistency between the iron sights and the red dot, and the optic is closer to the bore.

If your optic loses power or you transition suddenly from a darker to a brighter area, you can adjust more easily. You can quickly respond to changes because you won’t have to make realignments.

AR-15 1/3 Co-Witness Sights

With AR-15 1/3 co-witness sights, the optical sight mount is slightly above the iron sights, so you have to drop your head a little to align the two. That means you’ll see only the iron sights in the bottom third of the optic with your standard line of sight.

The optic will be slightly off-center from the bore, but the difference is slight enough that it typically doesn’t cause any problems for shooters.

When you work with this option, you’ll have the advantage of a less cluttered sight, giving you more visibility. If you need to see the field and target with maximum clarity, this may be your best option, making identifying your target easier. It can also allow for more comfortable neck positioning and reduce muscle strain.

So if you’ve decided to install sights for your weapon, there are a few considerations you should keep in mind to get started. You can use a scope lift mount to lower your optics to standard scope height.

Essentially, you will need to zero in on your eyes and then align them with each other. Are you working with 1/3rd third sights and want to go to absolute instead?

There are a few simple steps you can follow to get started, but keep in mind that you can customize them to fit your unique needs:

  • Zero the reticles: Start with the reticle with the optics turned off.
  • Confirm visibility: If you still need to, install the optics and ensure you can see the desired image.
  • Test your aim: To make sure everything is ready and on target, try firing a few shots from a range to check the accuracy of your zero.
  • Align the optics with the reticles: When you are satisfied that everything is in order, get the desired image, turn on the red dot, and align the reticle with the reticles.
  • Confirm and shoot: Test fire to confirm your zero with just a red dot, then make the necessary adjustments.

In conclusion, choosing which witness sights are best for you depends on your needs. Your choice should mostly depend on your preference and shooting style, but matching your witness sights to your firearm and its use is essential.

These are not hard-and-fast rules but helpful guidelines to help you take better aim and get a clean, accurate shot.

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