Co-Witness Sights: Explaining Absolute & Lower 1/3 Sights

Most people think that the BEST way to get the best shot is only by buying the best red dots the world offers.

Many people think that the ONLY way to ensure accuracy is by getting a good optic for their gun. While that is important, they seem to forget that even the best optic can still fail.

This is why co-witness sights, albeit overlooked, are still a very important part of your gun, even to those in the military.

Co-witness sights are a way to ensure the best accuracy and target acquisition to be able to aim your shot properly and hit your target every time.

This article will give you a full rundown of what a co-witness is and how to make the most out of them!

What Are Co-Witness Sights?

The term co-witness refers to the relationship between iron sights and modern optics (e.g., red dot) on a rifle.

Co-witnessing works when the iron sights are in line with the red dot to make a more precise shot.

When this goal is achieved, you can say that your optic and iron sights can work together as co-witness sights.

Co-witnesses give you better accuracy and give you a backup in case the main optic fails.

Should there be any problems with your main optic or if the optic is turned off, co-witness sights allow you another means to aim properly.

Co-witnessing also refers to the ability to view your iron sights through the main optic, whether they’re red dots or holographic sights.

NOTE: You can tell that your sights have been co witnessed when you can fire accurately through both the iron sights and the optic. Any shots you make through the irons and the red dot should be landing in the same place. 

While co-witnessing is most used when referring to AR 15s, it can also apply to any firearm, including rifles and pistols. 

Types of Co-Witness Sights

There are two main co-sighting systems: Absolute or 1/3 co-witness.

These two co-witnessing methods are achieved by adjusting the heights of the riser mounts. 

However, you may encounter a firearm, like the AK, for example, which will not allow you to achieve any kind of co-witness set-up other than a lower 1/3 co-witness set-up.

1. Absolute Co-Witness

When you position your sights so that the red dot is positioned ON TOP of the front sight post of the firearm and aligned with the iron sights, that setup is considered to be an absolute co-witness.

With an absolute co-witness sight, the iron sights are fully aligned with the red dot and are fully visible when viewed through the optic’s viewing window.

The optical sight mount and iron sights are on the same height for this setup. This type of setup is usually achieved by using a .83-inch riser mount on your rifle.

This kind of setup makes it easier to adjust to lighting changes and makes it a breeze to switch from your main red dot optic to your backup irons.

However, this means that the sight picture can be cluttered, so it can be difficult to completely visualize the target. This setup is best for flip-up iron sights.

2. Lower 1/3 Co-Witness

As the name implies, a lower ⅓ co-witness sight set up occupies only the lower third of the optic.

This type of setup involves placing the optical sight on an elevated mount to show a red dot that hovers above the top of the front sight post.

This offers a wider view of the optic and is recommended for those who are distracted from the red dot by the front sight post. 

The advantage of this setup is that you get maximum visibility for a less cluttered sight picture.

However, shifting positions while shooting may cause strain on your head and neck.

It may also result in more inconsistent shots due to the constant changes in position to use both the optic and the iron sights.

This type of setup is best for fixed iron sights and utilizes a 1-inch riser on the optic.

3. No Co-Witness/Pop-Up Sights

This is a lesser-known option that might be worth some consideration.

While pop-up sights are technically classified as a sub-type of absolute sights, they are so distinct that they may as well be discussed separately. 

Pop-up sights can hit the sweet spot between visibility and reliance. If you would prefer to use a single optic, pop-up sights can be lowered out of the way for easy shooting.

If your red dot sight fails for any reason, a touch of the button is all you need to activate the front and rear sights for continuous shooting. 

Absolute vs. Lower 1/3 Co-Witness Sights

The main difference between absolute co-witness and lower 1/3 co-witness sights is really how much of the iron sights, especially the front sight, are visible through the sight picture.

Other than this, what is the difference between an absolute co-witness and lower co-witness sight?

The other way absolute co-witness sights differ from lower 1/3 co-witness sights is in the HEIGHT at which they are mounted.

• With absolute co-witness sights, the optical sight and iron sights are mounted at the same height.
• While for a lower 1/3 co-witness sight, the co-witness optic is mounted higher than the iron sight.

Additionally, for absolute co-witness sights, the optics are positioned closer to the bore or the center of the barrel.

IMPORTANT NOTE: The further an optic is positioned from the bore, the more difficult it is to sight in accurately at various distances.

For lower 1/3 co-witness sights, the optics are mounted slightly off-center and a little further from the bore.

Should You Use Absolute or Lower 1/3 Co-Witness Sights?

Both absolute and lower 1/3 co-witness sights have their pros and cons.

In the end, it boils down to personal preference or if there are any hindrances in what your gun can handle.

• An absolute co-witness is recommended for those who have FLIP-UP iron sights as they won’t get in the way of your shooting.
  • They are also best if you are more comfortable not having to change positions to switch between sighting systems.
• A lower 1/3 co-witness is recommended for those who use FIXED sights. This sighting system will allow you to have a less cluttered sight picture even with your iron sights.
  • If you’re fine with having to shift the position of your head slightly when aiming at the target with the different sights, then this is the one for you.

Why Should You Use Co-Witness Sights?

While modern optics are very accurate, precise tools, they also mostly rely on batteries.

Anything that relies on batteries is bound to run into issues or die.

This can be disastrous in a self-defense situation or when you’re on the hunt. You may be cornered or finally have that one handsome buck you’ve had your eyes on, only for your optics to fail.

In such a worst-case scenario, you still need to know how to aim when you shoot. It can be disastrous if you blindly shoot without knowing where your shots are going. 

This is when back-up sights come into play!

In the case of main optic failure, co-witness sights allow you to quickly shift to using the iron sights to shoot. 

How to Set Up and Zero Co-Witness Sights

Now that you’ve decided to set up co-witness sight on your gun, let’s go over how to set them up and zero them in with 4 simple steps.

Step 1: Mount and Zero-In Your Iron Sights

Thanks to the popularity of various optics and sights, more and more rifles are being sold without iron sights.

As such, you’re going to have to buy your own iron sights.

You may opt to get flip-up iron sights or fixed iron sights, or even a combination of these two types of iron sights.

Choose the appropriate rail height depending on the kind of co-witness set-up you prefer.

• For an absolute co-witness, you will need a .83″ mount
• For a lower co-witness, a 1″ riser is preferred.

Once the iron sights are set up on your rifle, zero them in according to your preferences. Don’t be afraid to take your time using the windage and elevation adjustments to get it properly dialed in. 

Some people prefer to mount the iron sights and the optic simultaneously. If you are one of those people, be sure to keep the optic OFF while zeroing in your iron sights. 

Step 2: Mount Your Optics

Once you’re sure that your iron sight is properly zeroed in, it’s time to mount your optic onto your rifle, whether they be reflex sights or red dots.

You might need a riser depending on the type of co-witness set-up you’re planning on. 

When mounting your red dot or reflex sight onto your rifle, be aware of the iron sights you have already installed.

Be sure that it doesn’t interfere with the sights when installing the optic!

Implement your preferred adjustments and zero them in accordingly so that they’re in a comfortable position.

Step 3: Adjust and Align Your Optics With the Iron Sights

Now that both sights are in place and properly zeroed, adjust the optic so that the reticle aligns with the iron sights. 

It is best to do this with the help of a bipod or lead sled.

Step 4: Run a Test Fire

Now that you’ve aligned your optics and iron sights, take the rifle to the range and fire a few shots at a target to be sure that they’ve both been zeroed in properly.

Turn on your optic. Try to get as good of an image as you can while aiming with the rear iron sight. When you think you’re ready, take a shot.

Take note of where the shot is landing.

Did it land where the red dot is located on the reticle?

If so, this is a sign that you have successfully co witnessed your sights.

If it didn’t, you might need to make a few adjustments until the shots you take with the rear sight are in line with the red dot.

Continue doing so until any shots you make with the iron sights land in the SAME PLACE the red dot is pointing at.

Once you are successful in this, you have successfully co-witnessed your sights!

Recommendations for Fixed Iron Sights

Before we end our guide, we’re going to recommend a couple of products you can consider if you’re thinking of getting a co-witness sights setup.

You will notice that there is only one recommendation on this first list as it is the absolute best on the market.

It’s the best for lower 1/3 co-sighting.

In general, any fixed iron sights for AR15s from Daniel Defense are great choices. Of all of them, however, our top pick is:

1. Daniel Defense A1.5 Fixed Iron Sights

Daniel Defense is known for and is undeniably the best manufacturer of fixed sights. Of all their products, the best is the A1.5 Fixed Iron Sights. 

These fixed sights made of 6061 – T6 aircraft-grade aluminum are both light and durable at the same time.

You are assured of longevity and durability with the Type III Hard Coat military specification anodizing, making these sights resistant to corrosion and oxidation. 

These sights designed for the AR platform are snag-free, incredibly accurate, and very easy to use. 

Recommendations for Flip Up Iron Sights

Flip-up sights are some of the most popular iron sights out today.

They are best for absolute co-sighting.

1. Troy Industries Micro HK Style Front and Rear Iron Sights

These flip-up iron sights, made of stainless steel and aluminum, are extremely light, reliable, and durable.

You don’t have to worry about them weighing down your rifle, as they weigh less than 3 ounces. 

They are locked in tight with two locking detent balls but are easily deployed with spring action and can be secured with your everyday flat head screwdriver. 

2. Magpul Gen 2 Rear AR-15 Flip-Up Sights

These sights proudly made in the US are made of a tough polymer that makes them resistant to impact, bumps, and scratches.

Despite this, it will not weigh down your rifle as it is still extremely lightweight. 

This is a great product even for beginners due to its simple design and ease of use. It pops up and down easily and comes with knobs that can easily adjust windage. 

3. Souforce Tactical Front & Rear Iron Sight Set

The Souforce Tactical Iron Sight Set is the best option for those on a BUDGET. 

It has a T6 heat-treated body made of 6061 aluminum. When flipped up, they fully lock into position and fold flat with a simple press of the release button.

They are easily adjusted with traditional windage and elevation adjustment knobs. 

In short, this is a very affordable, durable, and easy-to-use sight that’s great for everyone from beginners to professionals.

Recommendations for Red Dot Sights

Red dots are some of the most popular optics out there today.

They are great for co-sighting for whatever setup you have.

 1. Aimpoint PRO

The Aimpoint Patrol Rifle Optic (PRO) is in a league of its own!

It’s known to be one of the best red dot sights out there — according to everyone from casual shooters to military and law enforcement officers. 

It’s legendary for its amazing durability to withstand extreme conditions, as well as its extremely long battery life.

In fact, it is said that the human body will shut down before the Aimpoint PRO will!

The Aimpoint PRO boasts a 2 MOA red dot with 10 brightness levels. Of these levels, 4 of them are night-vision compatible. 

2. EOTECH 512 Red Dot Sight

While EOTECH is known for holographic sights, the 512 qualifies enough to earn a spot as one of our recommendations for red dots. In fact, we’d say that it’s perfect for first-time buyers. 

The rugged build on this red dot sight means that it can take the drops and clumsiness of a beginner and is even fog-proof and waterproof. 

It features a 68 MOA circle with a 1 MOA red dot with 20 brightness levels. 

3. Vortex Optics Strikefire II

The Vortex Optics Strikefire II red dot sight is perfect for those on a budget.

It is priced under $200 but still offers superb quality with a compact, lightweight, rugged body that can withstand water, impact, and fog.

The Vortex Strikefire Optics II features a 30 mm objective lens with a 4 MOA daylight bright reticle and 10 brightness levels, 2 of which are night vision device compatible.

Summary

Still not 100% clear about all the information we just provided?

Here’s a quick rundown of all the important things we discussed in this guide:

• Co witnessing refers to the practice of having iron sights and optical sights that line up with each other to work together in tandem for better target acquisition.
  • The point of co witnessing is to give the shooter the option to shoot with their iron sights even when their reflex sight or red dot optic is turned off or damaged. Co witnessed sights are extremely important in self-defense situations!
• There are two main types of co-witness setups: Absolute co-witness and lower 1/3 co-witness.
  • An absolute co-witness has the whole front iron sight visible through the sight picture.
  • The lower 1/3 co-witness has the front sight occupying only the lower 1/3 of the sight picture.
• This height difference is mostly accomplished by using risers to adjust the height of the optic.
• An absolute co-witness is recommended for those with folding iron sights, while a lower co-witness is recommended for those with iron sights that are fixed.

Interested in setting up your co-witness sights? Take a look at our top product recommendations for some options.

We hope this helpful article cleared up any questions you had about co-witness sights!

Happy hunting and shooting!