Where To Mount Red Dot On AR [Ideal Optic Distance To Eye]

optic distance to eye guide

In this guide, we're going to show you where to mount red dot on AR or other rifles to maximize field of view and make your rifle setup look good.

Check it out.

Save Up To 35% on Trijicon Red Dot Sights

How Far Forward To Mount Red Dot

Mount A Red Dot Closer To The Eye

X95 where to mount optic

How far back to mount red dot scope helps: 

  • Acquire the sight picture faster and have a bigger field of view.
  • Avoid optic lens frame getting in the way
  • More flexible cheek positions and still able to see the reticle
  • Much better for cross-eye dominance shooters
scalarworks aimpoint micro on mk18

Better FOV & Speed - Bring it right in front of your eye & shoot! Using a large field of optics like the EOTech EXPS3, Holosun 510C, and other large window lenses, so the shooter can aim with two eyes open focus on the target while the reticle just superimposes over the target.

When To Back Off A Little? - Just make sure you don't place the optic too close to the point where the frame of the optic is obstructing your situational awareness.

Moving the sight closer to the eye and aim with two eyes open also helps cross eye dominant shooters to have better sight picture acuity when using a parallax free optic.

Forward Mounted Red Dot 


Forward mounted red dot installation is generally for rifle with limited rail space such as an AK without an railed dust cover.

When the user mounts the sight forward, the shooter can drive the gun faster to the target and also acquire sight pictures fairly quickly. However, the field of view will get smaller.

Other times, mounting a lightweight red dot more forward allows for more rail space to mount a night vision scope or reflex magnifier optic, and it doesn't significantly shift the rifle's center of gravity.

Check out other optic mounting locations for an AR rifle here

Proper Eye Relief For Scope - Red Dot Magnifier Setup

As a rule of thumb, keeping 3 - 4" eye relief distance when using a magnified optic to get a good sight picture without the scope shadow and a good cheek weld position.

trijicon rmr with vortex micro 3x

Referenced USAF Minot AFB 5th Security Forces

Most magnified scopes on the market today have about 3-4" eye relief distance, so the shooter can comfortably get behind the rifle to prevent scope bite when shooting a heavy recoil rifle, and it provides enough head clearance for shooters wearing tactical helmets without bumping into the ocular lens.

Optic Height

sig romeo 5 red dot pov

Once the horizontal distance between optic and eye is figured out for your setup, the next is to make sure the optic sits at the right height vertically to meet the eye.

There are tall mount and low mount. Low optic mount works for any weapon system that has slight or no offset distance between the top rail and stock cheekweld.

Absolute low optic height mount works for something like the AK, where the cheekweld already puts the shooter's eye right in alignment with the optic.

Common FAQ

Is There Eye Relief Distance For A 1X Prism Sight?

A 1X prism sight has a shorter eye relief (Typically 3 - 4"). Typically A 1X prism sight feels like a 1X red dot, but it's a scope with a detailed glass etched reticle that never dies even if the battery does.

Learn about red dot VS prism sight here

Does Optic Distance To Eye Affect Reticle Parallax?


Optic distance to the eye doesn't affect reticle parallax unless the head position shifts significantly in relation to the target plane.

Does Optic Distance Fix Astigmatism?

Optic distance from eye does not have anything to do with astigmatism.

shooters with astigmatism see this

Astigmatism has to do with the imperfection in the curvature of your eye and light refraction that causes blurred reticle and sight picture.

Putting the optic closer or further doesn't have any effect on reticle clarity if the shooter has astigmatism.

Try a prism sight or a red dot reticle size between 3 and 8 MOA.

Check out optics best for shooters with astigmatism 

Ying Xu

I was a former US Air Force ICBM operator, and now I'm a veteran creating fun firearm accessories content. I also work as the search engine expert for BadAssOptic.com