Simple Explanation: How Do Red Dot Sights Work?

Red dot sights, or reflex sights, are innovative electro-optical devices crafted to streamline target acquisition and bolster accuracy.

Unlike traditional iron sights, which demand aligning multiple elements, red dot sights simplify the process by allowing shooters to place the red dot directly on the target. 

This intuitive design enables shooters to quickly engage targets, even at 100 yards or more, without requiring intricate sight alignment. They can be used on various firearms, from pistols to rifles and shotguns.

Their defining characteristic is using a simple reticle, typically a dot, sometimes green, providing simplicity for shooters.

Originating in the mid-70s, these sights have undergone advancements over the past 40+ years, notably in battery life, clarity, and quality.

Understanding how red dot sights work is essential for maximizing their potential on the range or field. Integrating a red dot sight into your setup can elevate your shooting experience, whether you’re a seasoned marksman or a novice shooter.

Now let’s discuss the details of how do red dot sights work.

How Do Red Dot Sights Works

How Do Red Dot Sights Works

Red dot sights operate on a simple technological magic, primarily based on the Pepper’s Ghost principle.

Inside the sight, there are plates of glass arranged in such a way that when light passes through them, it reflects off a spherical mirror onto a LED positioned at the focal axis. This creates a red light that forms the reticle visible to the shooter.

The key component is a special coating on the glass that allows the LED light to pass through while disrupting the reflection of the surrounding environment.

When a shooter looks through the sight, they see a red dot superimposed on the target. This dot is created by a beam of light reflecting off an angled piece of glass onto the shooter’s eye.

The size of the dot is adjustable and measured in MOA, with larger dots facilitating quicker target, while smaller dots are preferred for shooting at moderate distances.

The aperture hole in the sight covers the target, making it significantly easier to aim accurately.

Why Use a Red Dot Sight?


Red dot sights offer a significant speed advantage over standard iron sights in defensive applications and competition shooting.

Compared to traditional iron sights, which require precise alignment and can be challenging to acquire targets quickly, red dot sights provide a much faster and more intuitive aiming experience. 

This advantage is particularly evident in high-pressure situations where split-second decisions matter most.


Red dot sights are valued for accuracy, offering speedy target acquisition and precise aiming.

Even at longer distances, when paired with a magnifier or used alongside prismatic sights, red dot sights maintain remarkable accuracy. This makes them suitable for various firearms, from general-purpose tactical rifles to precision rifles like the AR-15.

As someone who values both speed and accuracy in shooting, I have found red dot sights indispensable for enhancing defensive accuracy and general training, replacing traditional iron sights for many tasks.


One of the main reasons shooters opt for red dot sights is their simplicity. Unlike traditional iron sights, which require aligning the front and rear sights with the target, red dot sights offer an easy setup process.

Once properly zeroed in on the firearm, acquiring the target is a matter of placing the red dot on it and triggering the shot. 

This makes red dot sights ideal for close-range shooting, where speed and accuracy are paramount.

Limitations of Red Dot Sights:


Red dot sights can be an excellent solution for hunting or defensive shooting at moderate ranges. However, they may not meet the user’s needs for long-range shooting. Unlike highly magnified optics, red dot sights are typically designed for ranges within a certain threshold.

This means that shooters may need help to achieve the desired level of precision for engagements beyond their effective range.


Another limitation is battery power. Despite significant advances in contemporary red dot sights, batteries can fail at an inopportune moment.

However, companies like Holosun have introduced innovative solutions, such as solar power, to mitigate this issue. To avoid unexpected failures, it is recommended that batteries be regularly checked and replaced every few months.

Vision Issues:

Using red dot sights can be challenging for shooters with astigmatism or sensitivity to bright lights. The red dot may appear fuzzy or warped, especially when set to adjustable brightness levels.

Some users may find relief by using green dot sights or wearing polarized glasses to reduce blurring.

Types of Red Dot Sights:

When exploring the types of red dot sights, it’s essential to understand the nuances of each, including reflex, prismatic, and holographic sights.


Reflex sights utilize a translucent mirror or beam of LED light to project a reticle onto a target.

These sights are famous for their simplicity and affordability, with brands like Holosun offering reliable options ranging from $20 to $500. 

A significant benefit of reflex sights is their sharp, accurate red dot that remains illuminated even if the battery fails.


Prismatic sights operate on the principle of utilizing a prism and lens system to enhance image sharpness and magnification.

Unlike traditional red dots, prismatic sights offer a series of sharp reticles for precise aiming at the target. A major benefit of prismatic sights is their etched reticles, which ensure a true red dot even if the battery fails.

Despite their functionality, prismatic sights may be more expensive than red dot sights.


Holographic sights utilize laser reflectors to project a great image onto an output screen.

Unlike traditional red dot sights, they offer a three-dimensional reticle display, providing shooters with enhanced accuracy and a precise perceived point of impact. 

These sights are known for their highly accurate performance, although their complexity and cost may be higher than those of other types of red dot sights.

Which Type of Pistol Red Dot Is Best?

The answer depends on various factors such as applications, merits, needs, and preferences. So it’s hard to say which is the best. It all depends on what you need and like.

  • Reflex sights are affordable and ideal for small firearms like pistols. Due to their versatility, they suit both pistol applications and rifle builds.
  • Prismatic sights, like the Trijicon ACOG, offer clarity and reliability, with the added advantage of etched reticles for continued functionality even if batteries fail.
  • Holographic sights benefit from reduced parallax for downrange shooting, making them suitable for short to mid-range engagements.

Basically, you can make any of these sights work if you think about what you need before buying. Don’t just focus on how they work, but also consider their features and your budget.

How Do Red Dot Sights Works

My Final Conclusion:

In conclusion, due to relentless technological development, whether you opt for a reflex, prism, or holographic optic, red dot sights stand out in today’s market.

Conducting thorough homework before investing ensures the best value. Custom-made holsters tailored to your model can enhance your shooting experience. 

Exploring recommended products and resources like Vedder Holsters’ Resources Page provides valuable insights. Staying connected with reputable brands ensures you remain up-to-date with the latest offerings.

My Friends Feedback:

In discussions about red dot sights, my friends often emphasize the importance of alignment. 

A lighted dot projected onto the lens allows for quick and accurate aiming, reminiscent of WW2 fighter plane gun sights. This principle of aligning the reflected dot with the target streamlines shooting, particularly in tactical situations. 

Reflex sights, with their illuminated reticles and infinite eye relief, offer shooters an intuitive aiming system, ensuring accuracy even at relatively short ranges. Understanding the role of lens reflection in projecting the red dot aids in efficient target acquisition.

Whether for a handgun or rifle, the goal remains the same: to place the dot at the centre of the target, whether in a competitive bullseye competition or a real-life encounter. 

However, weather, ammunition, and firearm quality can influence accuracy, highlighting both the benefits and downsides of relying on this simplified aiming system.

Common Questions Asked About How Do Red Dot Sights Works:

How effective are red dot sights?

Many shooters discover that they achieve greater accuracy using a red dot sight compared to traditional iron sights, especially over longer distances and in situations where speed is crucial.

Does a red dot sight always stay on?

Most modern variants of this system enter sleep mode after being inactive for a while, relying on motion to wake them up. Some users of newer models forget about the power button, assuming the optic will always wake up when they handle their weapon. This assumption can be dangerous.

Can you see a red dot sight at night?

Despite being a light source, the red dot should theoretically remain visible in any lighting condition. However, using a Red Dot Sight (RDS) in low-light environments presents its own challenges. Some users report issues such as the red dot glaring too brightly in the dark, which can overshadow the target view.

Can a red dot sight zoom?

Some users do use magnifiers with red dot sights. The highest magnification I’ve come across is 3x. Additionally, there are detachable and flip-to-side magnifiers that can be paired with certain red dot sights.

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