There is no single accessory that will have a greater impact on your firearm’s performance than your optic. A match-grade trigger or premium barrel can improve your group size, but switching from a red dot to a scope or vice-versa can fundamentally alter the way you use your firearm, the ranges it is capable of engaging at, and more.
That being the case, it’s essential to ensure you’re using the right optic for the job. Below, we’ll take an in-depth look at one of the most popular choices: micro red dots.
Definition of a Micro Red Dot
There’s no hard and fast rule on what constitutes a micro red dot. Generally, when people talk about micro red dots, they are referring to enclosed-emitter red dots with a lens diameter of around 20mm. However, it’s not uncommon for larger 25mm objective lens dots to be included in this category, either.
We generally draw a hard line at a 30mm window size. At that size or larger, a red dot can be considered full-size. At 20mm or below, a dot is pretty unquestionably micro. For the range in between, it’s largely up to the opinion of the user; what feels like a micro-dot on a full-sized rifle or shotgun might seem considerably larger on a compact PCC.
Reflex Sight vs. Red Dot
While the two are often used interchangeably in casual conversation, there are technical differences between a reflex sight and a red dot sight that can make a substantial difference in their applications.
We cover the distinction in-depth in our article on reflex sight vs red dot, but the short version is that all red dots are reflex sights, but not all reflex sights are red dots.
Reflex sights are a large, blanket category that covers essentially any optic that creates a reticle by projecting light onto a lens. This can include both open and enclosed emitter designs, as well as holographic optics.
Red dots are more restrictive, generally limited to enclosed-emitter optics that use a more traditional projection method rather than a holographic one.
When to Use a Micro Red Dot
Microdots offer a sort of middle ground between a mini reflex sight such as the Trijicon RMR and a full-sized 30mm red dot like a Vortex Strikefire II. They’re tougher than mini reflex sights on average and more capable of standing up to abuse. Because they feature enclosed emitters, they also tend to handle dirt and mud better, since they can be quickly and easily wiped clean if obscured.
Their size belies their durability, though, making them lighter and more compact options than full-size red dots. Whereas a 30mm red dot might be unwieldy on a highly compact subgun, a micro red dot is often right at home, despite being slightly larger than a mini reflex sight. A microdot is also an excellent choice for a red dot for a shotgun, as many designs are small enough to cowitness with standard iron sights.
This makes micro red dots an ideal option for users who prioritize size and weight savings, but also require the durability and reliability of a full-sized dot. Because their only real drawback is a slightly smaller objective window, there are few applications in which a micro red dot is not sufficient—other than those that call for an actual scope, of course.
Micro Red Dots & Magnifiers
A magnifier is a common upgrade for an AR-15 red dot, and like their full-sized brethren, microdots are quite easy to use with a red dot magnifier.
Pairing the two is usually no more complex than finding appropriate mounts to position them at the same height and installing them on a firearm. It’s worth noting, though, that for best performance, your magnifier will usually need to be zeroed to properly align with your red dot and center the reticle.
While often sold together, you need not limit yourself to a single brand or product line when building your red dot and magnifier combo. Different makes and manufacturers can typically be combined without issue, so long as they can be mounted at the same height.
For example, despite being from different manufacturers, you could easily combine a Primary Arms micro dot with a Holosun magnifier. Mounts are not universal, though, so take care that you are buying the correct one for your magnifier.
Choosing the Right Micro Red Dot
Picking a micro red dot is largely a matter of budget and personal preference. They all perform basically the same function—projecting a dot onto a glass lens—so the choice of make and model tends to come down to the details.
It’s important to consider factors such as durability and the manufacturer’s history of quality. These often scale with cost, but not always—in fact, durable, high-quality dots are rapidly becoming cheaper than ever. You will usually find that more affordable units tend to be light on features, though, so if you require night vision compatibility or a more sophisticated reticle, expect to pay a bit more.
Battery type is also a common consideration. Larger dots often take common batteries such as AA or AAA, which can be convenient for those who already have a large supply of those batteries on hand. Smaller microdots will typically utilize CR2032 cells, which have become increasingly easier to find and are now carried at most hardware and electronics stores. Some dots still utilize less common batteries, though, such as 1/3N, which can be more difficult to locate.
Lastly, you’ll want to consider your dot’s size and weight, even within the category of microdots. While all are relatively small and light, if you’re picking a micro dot for a piggyback or offset mount, you’ll want to stick particularly close to the small end of the scale, as even a 25mm dot can quickly become unwieldy in these use cases.
Popular Models
Below, we’ll take a quick look at some of the most popular micro red dots on the market.
Holosun 503
Holosun is a company long known for feature-rich optics and affordable price points. Their 503 series of micro red dots are no different, offering an innovative multiple reticle system that allows users to choose between a simple dot reticle or augment it with a large 64-moa circle for faster target acquisition at close range.
The 503 is also available with either a green or red reticle, and can even be had with Holosun’s solar backup technology.
Primary Arms SLx MD-25 Gen 2
Our MD-25 is on the large side for a microdot but makes up for it with a large window and an impressive feature set for its price point. Now in its second generation, the MD-25 not only features a battery life measured in tens of thousands of hours, but also motion-sensing technology to help stretch your battery as far as possible.
This technology automatically shuts off your sight after a few minutes of inactivity, then instantly brings it back to life as soon as movement is detected. In most cases, the reactivation is so seamless that you’ll wonder if it was ever turned off at all.
Available with a standard 2 MOA red dot or our more sophisticated ACSS-CQB reticle, the Primary Arms SLx MD-25 Gen 2 is a perfect dot for a compact duty or home defense rifle.
Sig Romeo and Juliet Combo
It’s easy enough to put together your own red dot and magnifier combo, but it’s even easier to buy a complete package. The Sig Romeo and Juliet combo delivers just that, offering users an all-in-one solution for short-to-mid-range aiming.
The Romeo5 is a strong micro red dot in its own right, offering both motion-sensing technology and night-vision compatibility all at a competitive price point. It’s IPX-7 rated for water resistance and can provide up to 40,000 hours of life on a single battery.
Complementing that performance is the Juliet3, a ruggedized 3x magnifier that comes equipped with a quick-disconnect and flip-to-side mount, allowing users to rapidly switch between magnified and unmagnified aiming, or remove the magnifier entirely for standalone use as a monocular.
Trijicon MRO
Last, but far from least, we have the Trijicon MRO, a battle-tested sight from a manufacturer with an unmatched reputation for ruggedness.
Trijicon is nearly synonymous with durability, and the MRO is no exception. It’s designed and tested for resilience against heat, water, impacts, and nearly any other strain that might be encountered in the field.
The MRO also sports a unique design with a larger front lens to help enhance field of view while keeping overall size and weight low.
Conclusion
Micro red dots aren’t the right choice for every build, but they are a good option for a wide range of applications. With the durability and performance of a full-size red dot at a reduced weight and footprint, they’re an excellent option for short- and mid-range firearms that place a priority on speed and compactness.
With a plethora of great options from brands like Trijicon, Sig, Holosun, and of course, Primary Arms, a micro red dot is a perfect choice for your next build.
