For fast acquisition of targets and an easy use sighting system with your AR15, you can’t beat a red dot sight.
These types of sights feature an illuminated “red dot” (although other reticle designs and colors are sometimes available – see below) that functions as an accurate aim point for the operator. An AR-15 red dot sight is primarily meant for targets within 100 yards, but it can also work for longer ranges – especially when paired with a magnifier.
How Does a Red Dot Sight Work?
In order to choose the best red dot sight for your AR-15, it is important to first learn how red dot sights work.
The red dot sight relies on non-magnifying reflectors to display the red dot. Basically, a small LED generates a colored dot of light, which reflects against a small spherical mirror. The mirror focuses the dot on a lens, which is what you see when you look through the sight.
On more advanced (and expensive) red dot sights, additional lenses may be added to the setup to eliminate “parallax”. What is parallax? It refers to changes in the position of the dot when you look at it from different angles.
For example – you put your gun in a vise with the red-dot sighted on your target’s bulls-eye. When you move your head to a different angle and look through the sight, is the dot still on the bulls-eye? If the answer is yes – that means your red dot is “parallax-free”. This enhances the overall accuracy and usability of the sight. But be prepared to pay a little extra for a truly parallax-free sight!
Different Types of AR-15 Red Dot Sights
Red Dot Sights come in many shapes and sizes. The most traditional style is the “tube” style. Those sights look a lot like a short scope (like the AT3 RD-50), while “open” style sights are more of a square shape (Eotech red dot sights are a good example of this).
Since the original release of this article, “Reflex” style red dots have become increasingly popular. They offer the smallest footprint and lightest weight and can often increase time to target better than a tube-style red dot. They are also very popular mounted on the slide of certain handguns. A good example of a Reflex-style red dot is the AT3 ARO.
Now that you know more about the overall styles of Red Dots, the dot size, dot pattern, and dot color are the next considerations when choosing the correct red dot sight for your AR-15. You are the operator so your eyes, usage, the mission package, and the Configuration Of Your AR-15 Would Come Into Play In Choosing Your Red Dot Sight.
The dot size should be big enough for you to easily see, but not too large to obscure targets. Dot size is typically measured in MOA (“minutes of angle”). Essentially, 1 MOA means roughly 1″ at 100 yards. So if you have a 5 MOA dot, that means this dot covers a 5″ area on a target 100 yards away. For a general use AR-15 red dot sight, we recommend MOA between 1 and 4 MOA. Anything larger than 4 MOA may just get in the way. You may opt for a larger dot if you plan on mostly engaging targets at <100 yards.
The dot pattern (AKA the reticle) is largely a personal preference. Most sights have a dot (hence the name red dot), but you can also get reticles shaped like crosshairs, or many other patterns, such as a circle with a dot. Some sights have adjustable reticles and allow you to quickly switch between different reticle styles.
The last main choice is the Color Of The Dot.
Wait – it’s a red dot sight so the dot is going to be red, right?
Not necessarily – green and blue are also available. From our experience, Red Is The Best All-Around Color, and green could be easier seen in bright conditions (this is because green is at the center of the visible spectrum). It’s best to try a couple of different sights and see what you prefer.
AR-15 Red Dot Sights vs Scopes
For a sight that works well on shorter-range shooting (less than 300 yards), the red dot sight can be a great choice. They typically weigh less than a scope and are much better for quick target acquisition. Also, there will be no “tube effect” that is typical with a scope (due to the varying eye relief on scopes). Basically, a red dot is much simpler to use but lacks the magnification of a scope. Another major advantage to a non-magnified red dot is the ability to shoot with both eyes open. This enhances your situational awareness and prevents “tunnel vision”.
If you want some magnification, one option is to get a flip-to-side magnifier that goes behind your red dot. This allows you to flip the magnifier to quickly magnify your red dot for long distance shots. Despite that added weight, this is a versatile option that is worth looking into. Some red dot sights are available in a kit that includes the magnifier, like the Magnified Red Dot Kit pictured below.
Perhaps the biggest downside of a red dot sight is most require batteries. No Batteries, No Dot! But on most red-dots, batteries last so long it’s not an issue. For example, on the RD-50 Red Dot Sight, the battery lasts up to 50,000 hours between replacements.
Red Dots with Astigmatism
If you are new to Red Dots and can’t seem to get a clear dot, it may not be the sight, you may have a red dot astigmatism. You can learn more about this topic in our article AR-15 Red Dot Sights and Astigmatism.
Best AR-15 Red Dot Sights
There are many choices available for red dots, and everyone seems to have an opinion on the best red dot sight for AR15.
But we have 3 categories of recommendations: Best Value, Best Overall, And Other Excellent Red Dot Sights.
Best Value Red Dot Sights for AR 15: AT3 Red Dot Sights
Looking for a great red dot sight on a budget? AT3 red dot sights are the place to start, with many models to choose from. Since the original publish date of this article, the selection has expanded. The top choice is still the same, however. The best value red dot sight is…
At a price (still) under $100, the AT3 RD-50 PRO Red Dot Sight is an unbeatable value. It’s tough, lightweight, accurate, and easy to use. The RD-50 PRO features a crisp 2 MOA dot, a lightweight riser with several height configurations, and an armored housing with integrated lens caps.
Other key features are a waterproof, shockproof design; crystal-clear multi-coated lenses; and up to 50,000 hr of battery life. Plus, all AT3 products are backed by a transferable Lifetime Warranty.
Included with the RD-50 PRO is the PRO-MOUNT Riser – a premium lightweight riser mount that serves as the perfect companion for any AR-15. There are 2 mounts heights available – a medium .83″ riser for “absolute” cowitness with AR iron sights, and a 1″ high riser for lower 1/3 cowitness. If you need additional information on cowitness and which method will work best for you, check out this article.
In addition, the RD-50 PRO includes RD-ARMOR – a cover with integrated lens caps that protects your red dot sight from scratches, dust, moisture, and other damage.
The AT3 LEOS Red Dot Sight is designed for the AR-15 rifle and is packed with features like red or green targeting laser, integrated riser mount, flip-up lens caps, and tool-free windage & elevation adjustment. Both the laser and red dot are controlled with easy push-button controls.
Just like the RD-50-PRO, it features up to 50,000 hr battery life, and a durable, waterproof, and shock-resistant design that unfailingly stays on target. Pick up the red laser version for just $124.99 or step up to the green laser version for $159.99.
For an accurate, dependable AR-15 red dot sight that’s packed with features, the AT3 LEOS can’t be beaten.
[2021 Update] – More Value Red Dots from AT3
The ARO is a traditional reflex sight that has had a boom in popularity since the original publishing of this article. It provides top technology, a huge FOV, and multiple mounting styles (choose between a low mount or Absolute Co-Witness mount). This sight is perfect on your AR 15, AK-47, or shotgun. These red dots have become increasingly popular on some hunting guns too. Grab an ARO reflex sight today – prices start at $134.99.
The AT3 RCO is a fantastic value and has become a favorite among shooters since it launched. The RCO includes a rugged housing, riser, and spacer for absolute co-witness and lower ⅓ co-witness, 2 MOA/62 MOA reticle dot-and-circle with holdovers, flip-up clear lens caps, 11 digitally adjustable brightness settings, and, like all AT3 Red Dots, a transferable Lifetime Warranty. The AT3 RCO retails for $159.99
Best Overall AR-15 Red Dot Sight:
(Note – all links for the following items redirect to Amazon – we’ve found that they have the best pricing and availability for this sight)
When this article was first published, the Trijicon MRO was named the best overall Red Dot sight. The Trijicon MRO is still a great Red Dot Sight for AR-15 but a lot has changed in the red dot game since then. We think the best overall AR-15 Red Dot Sight now is…
The EOTECH XPS2 is a simple, lightweight, and effective red dot. There are multiple reticle options, but the best overall feature of the reticles are the multiple holdover points. The large outer circle at the bottom will be accurate for close range shots at 7 yards while the other aiming points are suitable for more standard AR15 ranges. You are able to have a quick offset marker in the reticle to account for close up shots. The large outer circle is a 68 MOA circle which helps get on targets faster as well. This large circle is also good for shotguns – taking into consideration shot spreads.
The XPS2 has a fairly large lens which aids in FOV and situational awareness. Like all EOTECH products, the XPS2 is widely known and tested to be very reliable and durable. It also provides all the “standard” features: waterproof, fog proof, co-witnessing is an option, using a magnifier is an option, long battery life, and a ton of brightness settings.
EOTech is a premier manufacturer of Holographic Red Dot Sights that allow heads-up, 2-eyes-open shooting. EOTech red dot sights come in many different styles and reticles, some of which are made for specific calibers like .223, .308, and .300 Blackout.
What makes the EOTech sights so great? For one, they are reliable – these sights are used extensively in combat and law enforcement. They also have excellent low-parallax optics and unique rectangle-shaped lenses for a wide field of view. Many of the EOTech red dot sights are also night-vision compatible.
In 2015, EOtech’s parent company lost a fraud lawsuit, where they were implicated in knowingly selling defective sights to the US military and government agencies. The company recalled many red dot sights after this, and they say they have since addressed the issues, but this incident damaged EOtech’s reputation in the firearms community.
Now that these issues are addressed, we think that EOtech sights are still an excellent choice. Want to learn more about EOTech sights? Check out our selection guide and comparison chart.
Other Best Red Dot Sights
Even though the MRO isn’t on the top spot on our list anymore, it is still considered a great Red Dot.
Launched in 2015, the MRO (Miniature Rifle Optic) quickly became a favorite with the military, law enforcement, and serious shooters. The quality, functionality, durability, and decent price (under $500) of the MRO puts it ahead of many other sights.
Trijicon is best known for their legendary ACOG rifle scopes, which have been the go-to military optic for mid-range applications for over 20 years.
The Trijicon MRO red dot sight packs many of the best features of the ACOG into a small red-dot sight. The forged aircraft-grade housing is as durable as you’ll find and even waterproof up to 100 ft. The glass quality is superb, with exceptional clarity and a crisp red dot reticle. The MRO offers 3 choices of mounts – low, medium, and high – with the medium and high mounts designed for co-witness on AR-15.
Aimpoint is a Swedish optics company that makes red dot sights for civilian, police and military use. It is Aimpoint’s belief that a weapon sight should simplify aiming while performing reliably under the toughest conditions. And they most certainly succeed in that.
Aimpoint sights are regarded by many as the best sights on the market – and for good reason – they are nearly indestructible red dot sights with excellent battery life. Aimpoint sights are pricey, and the functionality is fairly basic, but you cannot go wrong with an Aimpoint.
Best AR-15 Red Dot Sight Comparison Chart
|Product||Price (MSRP)||Max Battery Life||Dot Size||Weight|
|Eotech XPS2||$575||1K Hours||1 MOA Dot & Ring||9.0oz|
|Trijicon MRO||$579||50K Hours||2 MOA||4.1oz|
|Aimpoint PRO||$445||30K Hours||2 MOA||7.8oz|
|AT3 RD-50 PRO||$99.99||50K Hours||2 MOA||3.6oz|
This chart compares some of the most popular red dot sight models on the key attributes of price, battery life, dot size, and weight.
One Last Tip
If there’s anyone that knows the AR-15 platform, it’s the US military. As a special offer for our readers, you can get the Official US Army Manual for AR-15/M4/M16 right now – for free. Click here to snag a copy.