Ammo & Gear Reviews

Red Dots Vs. Magnified Scopes: The Best Optic For Your AR-15

Guns and Gear Contributor

By Mark Grimsley,

One of the most important accessories to add to your AR-15 is an optic. Being able to place well aimed shots on target will increase a person’s confidence and trust in their rifle. But, since there are so many options available, choosing the right one can be difficult. The first consideration to deciding on an optic is to determine what application your rifle will be used for. Are you focused on close quarters combat (CQB) or more of a marksmanship roll? Red dot and magnified optics are viable options for both rolls but with their own advantages and disadvantages. Let’s look at both types of optics and see if you can determine which is the best for your set up.

The What And How Of Red Dots

A red dot is one of the simplest optics available. It is nothing more than a LED light that is reflected off the front lens of the optic. That reflection then gives you the ability to point and shoot at a target quickly. After the Aimpoint M68 Close Combat Optic was widely distributed by the U.S. military and accepted by the firearm community, the market exploded with competitors and mimics alike. As technology advanced, more options were made available that allowed for continuous operation of 3 to 5 years. Having an optic with the ability to be left on for years on end is a definite advantage.

The primary advantage of a red dot is having a 1x power optic that allows you to acquire targets and fire swiftly. This makes it particularly ideal for CQB engagements. Furthermore, with most red dots, these sights can be set up to allow for co-witnessing of iron sights. Essentially, co-witnessing is nothing more than aligning your red dot with your fixed, or flip-up, iron sights. There are several different techniques on co-witnessing that include absolute co-witness, lower 1/3 co-witness, or front sight only co-witness. These techniques allow the shooter to have multiple points of reference to make accurate shots on target. Or, you can use the red dot as the sole point of aim.

The Gaps Of Red Dots

Red dots excel in reflex shooting but are not perfect. Some may struggle to be accurate shooting with a red dot at distance. Shot placement can be dramatically hampered using a red dot as distance increases. But, one way to overcome this deficiency is to couple a magnifier with flip mount to the red dot. This will amplify the image to allow for longer shots. But, it will also add weight, cost and complexity to your set up.

Another gap to red dots has to do with the biology of your eye. Astigmatism can cause the quality of a red dot to be degraded or be a major issue due to the irregularity in your lens. The various levels of severity of astigmatisms will cause differences in clarity of the dot. For most, a slight astigmatism will make the red dot appear to be a starburst pattern. More sever defects will cause the dot to look oblong or appear to be several dots in a line. This may be something you will want to investigate before purchasing a red dot.

Are Magnified Optics Better?

The recent U.S. war in the Middle East saw a rise in the use of fixed power optics. The Trijicon ACOG was extensively used by the Marines in Iraq and Afghanistan as the primary optic which provided 4x magnification. This enabled Marines to be more confident and accurate at increasingly longer distances; especially in Afghanistan. Another great attribute of the ACOG, and most fixed powered optics, is the bullet drop compensated (BDC) reticle. A BDC provides predetermined points of aim integrated into the reticle for known distances to compensate for the drop of the bullet. This greatly assists the shooter in being more precise at ranges between 300 to 600 yards.

One major edge that the Trijicon ACOG has over red dots is ability to illuminate the reticle without a battery. The ACOG uses fiberoptic technology to light a reticle. Using ambient light, it is also able to manage the intensity of the reticle’s illumination. This feature allows the user to not be concerned about packing extra batteries or the scope failing when needed the most. While not all fixed powered optics are not illuminated in the same way, the ACOG is seen as the gold standard. Some variations of the ACOG will use batteries or will have no illumination at all. Definitely research the type of reticle that is used and how it is illuminated before buying.

Gaps To Fixed Power Optics

There are two major gaps when using a fixed powered optics. First, these scopes do not allow for co-witness of the iron sights. Due to the magnification, the optic will focus past the front sight post. Should the scope get damaged or fail, usage of the iron sights may be impossible. However, using a quick-disconnect mount will allow you to remove the optic without tools to use your iron sights.

The second gap is target acquisition within 25 yards. Because of the magnification, your target may be too close to determine where you are aiming. This will hamper your ability to consistently place shots on top of each other should your target be at “bad breath” distances. But, there are techniques that may remedy this issue. The Bindon Aiming Concept is a method of shooting with both eyes open when using a fixed powered optics. Your eyes will naturally converge the magnified reticle onto the target as seen by both eyes simultaneously. This will take some training to get use to but will help with quick target acquisition for CQB engagements.

Bridging The Gap

There is one type of optic that can accomplish both abilities that a red dot and a fix power scope were designed to do. A low power variable optic bridges the gap between these two types of optics by allowing the shooter to quickly acquire targets at a 1x power setting. It can also increase magnification to 4x, 6x, or even 8x power to stretch the legs of your rifle. The Vortex Razor HD Gen II 1-6x24mm is seen as the median 1-6x scope in the market and has been sought after by most serious shooters. Another great example is the Primary Arms 1-6x24mm ACSS scope which provides a quality and inexpensive option for any user to achieve near and long-distance accuracy.


It is extremely important to determine what application your AR-15 will serve. Understanding the advantages and disadvantages of red dots and fixed powered optics will help you determine which is right for your set up. Red dots are great options for target acquisition in CQB scenarios. Conversely, fixed power optics will increase accuracy at distances from 100 to 600 yards. However, low power variable optic scopes may be a great choice for some that is interested in combining short- and long-range shooting. Regardless what your optic purchase will be, the most important aspect of employing your AR-15 is to get training. Training will build your confidence and accuracy in every application.

Mark Grimsley is a writer for Mark is a former U.S. Army Officer that started his career as an enlisted Abrams crewman. He has served in 3 overseas tours that include Korea in 2002, Iraq in 2003 as a tank gunner and Afghanistan in 2010-11 as a logistics officer. He completed numerous schools in the Army to include Air Assault and Airborne. Currently, Mark is an Army spouse and enjoys running a YouTube channel. Click here to visit