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  • Post last modified:September 8, 2023

If you're new to shooting pistols with a red dot sight, you may be wondering if aligning pistol red dot co witness with iron sights is practical?

Yes and no.

This guide will address the question with some context to give shooters some practical tips, so you can decide what works.

Important Details To Point Out

Handgun red dot sight picture is never 100% co-witness like an rifle sight picture. There is always a slight angle to it, where the front iron is taller.

Use Case 1 - Casual Range Use

range day with hellcat

Iron sight main purpose : Sight picture alignment 

Aligning iron sights to the red dot on a pistol is absolutely helpful for finding the sight picture first. As far as shooting the gun goes, iron sight co-witness isn't required once the shooter is proficient at picking up the dot while focusing on the target.

There is nothing negative here about having iron sights, unless spending hundreds of dollars on a new pair of iron sights that you don't really use at all.

Use Case 2 - Initial Zeroing

holosun 507c x2 battery tray access

Iron sight main purpose : Serves as reference point to first center the reticle to roughly the bore  before expensing rounds to refine zero

Iron sights help the user to initially center a red dot reticle as close to the bore as possible, then dial in the adjustments.

The red dot reticle and the iron sights are TWO INDEPENDENT sighting systems on a handgun slide, so it's important to zero

It will be difficult to start with no aiming reference point, and waste ammo on the range to zero the optic.

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Use Case 3 - Having Difficulty Finding The Dot

Iron sight main purpose : Helps to find the dot if lost in the FOV

For shooters who struggle to find the dot faster, it's all about the sight picture angles.

Iron sights can help the shooter to index the iron sight and then find the red dot reticle.

Co-witness the iron sight to the dot doesn't guarantee faster sight acquisition. In some cases, it helps but for the most part, about the distance between the eye to the optic.

acss vulcan reticle pov

The closer the eye is to the optic, the more room there is to find the dot. The further away the eye is to a small optic window, the tighter the visible degree funnel there is.

This is where a larger window like the DeltaPoint Pro, Trijicon SRO & Holosun 507C ACSS Vulcan reticle helps the shooter a lot in finding the dot.

Use Case 4 - Sight Picture Angle & FOV

pistol red dot sight co witness

Iron sight main purpose : Serves as reference point to first center the reticle to roughly the bore  before expensing rounds to refine zero

When the shooter is target-focused, the reticle should superimpose on the target, and it should be in the middle of the field of view as much as possible. This means the shooter sees the sight picture at an angle with the front sight slightly taller. 

It's the same for a long slide pistol and sub compact.

Here is what it looks like:

fn509 trijicon sro pov in action

If you perfectly slave the iron to the red dot, this is what it looks like, and it's wasting a lot of FOV even on a Trijicon SRO.

In this case, it's much easier to lose the dot during recoil - Long story short, this is not optimal!

Use Case 5 - Phonetic Barriers & Direct Sun Light

shooting into the sun red dot sight

Iron sight main purpose : Use as back up sight

In low light situations, maybe your weapon light output is too high and it washes out the reticle and it takes a couple of seconds for your eyes to adjust in the dark.

When that happens, the iron sight will always be more visible for back up use.

The dot becomes very hard to see under the sun even if using a large dot reticle

The same thing happens when a much more powerful light source (Photonic Barrier) is blinding you & the reticle, which prevents you from focusing on the target, but the iron sight is still visible enough for the shooter to transition to maybe front sight focused shooting.

Use Case 6 - Optic Malfunction

holosun 507k dealing with melting snow

Iron sight main purpose : Use as back up sight

When the optic breaks, battery runs out or the LED emitter is somehow obscured by water, dirt or sand.

This is where the shooter transition to the iron sight if possible.

Learn more about enclosed red dot sight here

Use Case 7 - Suppressor Use


Iron sight main purpose :

  • To clear the suppressor can
  • To raise the optic if it sits too high on the slide

For suppressor use, tall iron sight allows the shooter to aim, and it just happens to co-witness with a red dot anyway.

Use Case 8 - Personal Defense

tlr6 lumen intensity

Iron sight main purpose : Not much use

In close-quarter defensive situations, the iron sight co-witness sight picture clarity is NOT important at all because when stress kicks in, all the theories go out of the window, and the eyes are focusing on the threat anyway.

Most documented defensive shooting incidents happen within 10 yards distance or even closer, and

This is where the benefit of using a red dot sight outweighs all the theories people have online.

Wrap Up

This guide serves as a quick guide to provide some context on when co witness is helpful and when it's not necessary. 

For the most part, co-witnessing the iron sight on the pistol isn't necessary especially for proficient shooters that are target focused & aim with both eyes open.