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