An Introduction to the Mechanics of Red Dot Sights

Chris G.

Exceptional marksmanship is usually the product of countless hours of training. However, having the right equipment is also a big part of improving that skill set. One such piece of equipment is the red dot sight. 

This guide explains how these simple yet effective optics have transformed the art of shooting. From the fundamental principles of light reflection and bending to the origin and progression of this ingenious instrument, we cover it all.

So, if you’re aiming to improve your shooting precision, getting to grips with the mechanics of your red dot sight is a smart first step.

What is a Red Dot Sight

A red dot sight is a non-magnifying reflector sight—sometimes called a reflex sight—utilized in conjunction with firearms to establish an aiming reference. It allows the shooter to aim with both eyes open, improving situational awareness, speed, precision of target acquisition, and comfort.

Red dot sights are popular in hunting, sport shooting, military and law enforcement operations, and recreational shooting. Their ease of use, quick target acquisition, and versatility make them a useful tool for shooters of all skill levels.

Red dots are also used in cameras and telescopes. These optical instruments have a narrow field of view, thus a red dot is often used to help orient them.

As an experienced hunter once said, ‘A red dot optic doesn’t make the target bigger, it just makes the shooter better.’

The Mechanics of A Red Dot Optic

a red dot sight showing how it works

How a red dot operates is pretty straightforward. Essentially, a red dot sight is built from three main components: a Light-Emitting Diode (LED) emitter, a mirror that collimates, and a spherical lens. The LED projects a beam onto the mirror. This mirror then bounces back the light towards the lens as a collimated image. The lens, with its unique curvature, disperses this light into a parallel beam, creating a red dot—called a reticule—that the user can see.

The mirror has a dielectric dichroic coating that reflects the red spectrum but allows most other light to pass through it. As such, the shooter simply hovers the red dot at the target. Given the right circumstances, the bullet will impact that “painted” target sight.

The beauty of this design lies in the fact that it lays the dot over the target without causing any shift in the user’s focus. This method of projecting the reticle is integral to the sight’s design, offering users unlimited eye relief and a design free from parallax. The result? Users can swiftly acquire their target, making red dot sights a popular pick for shooting in a range that’s close to medium.

History of Red Dot Reflex Sights

The history of red dot sights can be traced back to the late 20th century when advancements in optics and electronics paved the way for the development of these innovative aiming devices. The concept of a reflex sight, which laid the foundation for red dot sights, emerged in the 1970s. Engineers and designers began exploring the possibility of creating a sight that would allow for rapid target acquisition without the need for aligning traditional iron sights.

Aimpoint AB, a Swedish optics company, is credited with introducing one of the first commercially successful red dot sights. In 1975, Aimpoint unveiled the Aimpoint Electronic Sight, commonly known as the Aimpoint Mark I. This sight utilized a red dot reticle and was initially designed for use with hunting rifles.

The success and reliability of red dot sights led to their adoption by military forces around the world. The ability to acquire targets quickly and maintain situational awareness made red dot sights particularly valuable in tactical and combat scenarios.

Over the years, red dot sights have benefited from advancements in technology, including improvements in LED (Light Emitting Diode) technology, lens coatings, and battery efficiency. These innovations have contributed to increased battery life, durability, and overall performance.

Initially popular in military and law enforcement circles, red dot sights have expanded into various applications, including civilian firearms for self-defense, competitive shooting sports, and hunting. Their popularity has also grown in other fields, such as photography, where similar sights are used for quick framing and focusing.

Today, numerous manufacturers produce red dot sights with a wide range of designs, features, and price points. The market includes compact models for handguns, robust sights for rifles and shotguns, and even miniature red dot sights for use on pistols.

Pros and Cons of Using Red Dots

image of different red dot sight

The red dot sight, a widely accepted tool in shooting, has both merits and drawbacks that we should consider to understand its function in shooting techniques better.


  1. Quick Target Acquisition: Red dot sights allow for rapid target acquisition since users can simply place the illuminated dot on the target without the need to align traditional iron sights.
  2. Both-Eyes-Open Shooting: Red dot sights facilitate both-eyes-open shooting, providing users with increased situational awareness. This is particularly advantageous in dynamic and fast-paced scenarios.
  3. Parallax-Free Design: Red dot sights are designed to be parallax-free, ensuring that the reticle remains on the target plane regardless of the user’s eye position. This eliminates the need for precise eye alignment.
  4. Unlimited Eye Relief: These sights offer unlimited eye relief, allowing users to maintain a comfortable distance from the sight without sacrificing sight picture or experiencing distortion.
  5. Versatility: Red dot sights are versatile and can be used on a variety of firearms, including rifles, shotguns, and handguns. They are also employed in other fields, such as photography, for quick framing and focusing.
  6. Compact and Lightweight: Red dot sights are generally compact and lightweight, adding minimal weight and bulk to firearms. This makes them suitable for a wide range of applications without affecting the balance of the weapon.
  7. Increased Accuracy: Red dot sights contribute to improved accuracy by providing a precise aiming point, especially when shooting at varying distances.


  1. Battery Dependency: Most red dot sights are powered by batteries, and if the battery runs out, the sight becomes non-functional. Regular battery checks and replacements are necessary to avoid unexpected failures.
  2. Limited Magnification: Red dot sights are typically non-magnifying, providing a 1x magnification or no magnification at all. Users seeking magnification for long-range shooting may need additional optics.
  3. Cost: High-quality red dot sights can be relatively expensive. However, there are budget-friendly options available with fewer features.
  4. Durability Concerns: While many red dot sights are durable and built to withstand recoil, shock, and environmental factors, they’re still electronic products. That means they can still be severely damaged when subjected to certain extreme conditions.
  5. Potential for Lens Obstruction: The exposed nature of the sight’s lens leaves it susceptible to dirt, water, and other debris. Users need to be mindful of keeping the lens clear for optimal performance.
  6. Reticle Washout in Bright Sunlight: In extremely bright conditions, the red dot may appear less distinct, making it challenging to acquire the target accurately. Some sights address this issue with adjustable brightness settings and anti-glare coatings.


The advent of red dot sights has transformed the shooting field, providing a user-friendly and efficient targeting mechanism. These devices, with their ingenious design and rich history, come with a host of advantages, albeit a few limitations.

Gaining an understanding of how they work can help improve a shooter’s precision and speed, demonstrating their value in a range of shooting scenarios, from casual to competitive. Gaining proficiency in using red dots can make a notable difference to your shooting skills.

About the author

The name's Chris. Just a regular dude who loves firearms. I've been shooting since I was a kid. My old man taught me the ropes.

I'll never forget the first time I missed an easy shot on a buck, thanks to a bum scope. The image was fuzzier than my dog's butt. After that, I got obsessed with understanding scopes. What makes the good ones tick and the bad ones trash. After a few years and a few thousand bucks, I learned what separates the winners from the losers. Once I had a good stockpile of knowledge, I launched this site.

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