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A Brief Guide To Red Dot Sights For Pistols

pistol red dot

Chris Dumm for TTAG

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Wondering what red dot sights for pistols are for? They’re quite the bit of kit, as they allow for fast and accurate sight acquisition. Some people insist that they’re the only way to shoot, though iron sights have worked plenty well for a very long time, thank you very much.

So, what are they?

Mk III reflector sight, commonly used on anti-aircraft guns in WWII. Credit: Fountains of Bryn Mawr/Wikimedia Commons/CC-BY-SA

The modern red dot sight is just a new-fangled type of reflex sight, a sighting system developed for anti-aircraft guns in the early 20th century. Reflex sights – this is the most basic version possible here – superimpose an illuminated image (the reticle) over the sight picture, which moves as the gun does.

The reticle, once properly aligned, is parallel to the barrel out to infinity. Therefore, the dot gives you basically the point of impact up to the point where the bullet starts to drop beyond the area of the reticle projected onto the target.

Lucas Botkin, T.Rex Arms [CC BY-SA 3.0], via Wikimedia Commons
The reason why they’re popular is that they allow for getting on target fast, as you can get a sight picture far more quickly than you can using a flash front sight picture, and they’re still highly accurate. Granted, I can’t recall a point shooting vs. red dot comparison, as proper point-shooting techniques are also fast and reasonably accurate at close ranges, so I can’t speak to that.

The reticle on red dot sights, or the dot that you see, is sized in minutes-of-angle.

A minute of angle is an angular measurement, namely 1/60th of a 360-degree circle. This is the Reader’s Digest version here, so please feel free to expand in the comments if you like.

Sauer202 [CC BY-SA 4.0], via Wikimedia Commons
Now, bullets don’t actually fly straight; they rise and fall in a parabolic arc. Since optics of any sort don’t give you a picture that’s perfectly parallel to the barrel and other factors influence flight path (temperature, wind, humidity, etc.) the bullet won’t land exactly where an optic’s reticle sits on the target. Instead, it will land within a defined area.

Provided your optic is zeroed for your firearm, it will be within a defined area around where the reticle rests on the target.

Minutes of angle, again, are an angular measurement rather than a measurement of distance. Now, think of your gun forming the point of an isosceles triangle. The base of the triangle is the area where the bullet will land, and the minute of angle is the angle of the sides and the base. As the side gets longer, the base increases in size proportionally but the angle (the MOA) remains the same.

One minute of angle (1/60th of 360 degrees) works out to about 1.05 inch at 100 yards (which most people round down to 1 inch at 100 yards) then 2 inches at 200 yards and so on.

Why am I bothering to talk about all of this? Because it matters, of course! The larger the size of your red dot, the larger the area the bullet you shoot will potentially land in.

A small dot (the smallest available is generally 1 MOA with most red dot sights for pistols) will give you more precision, but makes sight acquisition slightly slower. A larger dot gives you faster sight acquisition, but it’s relatively less precise, especially at longer ranges.

Chris B. for TTAG

As a result, 3 MOA to 4 MOA red dot reticle optics are the most common for handguns as they tend to give you the best of both worlds. Sight acquisition is fast, but precision doesn’t suffer too much.

Red dots get much larger; Trijicon’s popular RMR red dots can be had with dots up to 13.25 MOA, which gets you on target seriously quick at short ranges, but are basically only good for the broad side of a barn at longer ranges.

Granted, Trijicon RMR sights can be had with an MOA anywhere from 1 MOA to 13.25 MOA, depending on the model you choose and your specific needs. Other makes/models, such as Burris FastFire red dot optics may have fewer options; the Burris FastFire 3 red dots are available only with 3 MOA or 8 MOA reticles. Vortex Viper optics come with 6 MOA dots only, and Vortex Venom red dots are available with 3 MOA or 6 MOA dots. Leupold’s DeltaPoint Pro can be had with a 2.5 or 7.5 MOA dot.

Many more models are available, of course; those are just some of the more popular makes and models.

As you can imagine, the point that we’re getting at here is that you need to pick a red dot sight that suits the purpose you have in mind for it. Are you looking for a fast sighting method for a CQB pistol? Are you looking for the utmost in precision shooting? Or do you want a combination of both of the above? Once you have that figured out, then pick a sight with an appropriate reticle size.

Now that we understand some of the basics, let’s get onto other features. All red dot optics are adjustable for windage and elevation for zeroing purposes. That needs to be done with any optic, be it a red dot, fixed or variable-powered scope and indeed even iron sights. That much speaks for itself.

Co-witnessed sights. Credit: Nick Leghorn/thetruthaboutguns.com

Something else to be aware of is co-witnessing. This is the use of iron sights in conjunction with a red dot optic.

Some optics are low-mounted so standard-height sights can be used, but many require you to install suppressor height sights in order to co-witness them. Proper use is to put the red dot over the front sight post, like a halo.

Some red dot optics are designed for use with many standard sights, but some are designed so that a specific rear sight must be installed for co-witnessing, such as the Leupold DeltaPoint Pro red dot, which requires you install a rear sight sold by Leupold.

Granted, Leupold is one of the leading makers of optics from red dots to rifle scopes, so you won’t go wrong buying their products…though they’re a tad expensive.

Do you plan on installing suppressor height sights? Or do you prefer your sights as they come? Make sure to choose the correct optic once you’ve figured this out for yourself. Most often, a suppressor-height front sight is needed at minimum, if not a suppressor height set installed as a matter of course.

Conner W. for TTAG

Illumination is another feature to be aware of. Some are battery-powered, some use passive illumination from fiber optics and/or tritium in order to illuminate the optic. The former is often brighter, but requires batteries. The latter requires no batteries, and works in low-light environments, but may not be quite as bright.

Typically, battery-powered illuminated red dots use an LED. Brightness is usually adjustable. Battery life depends on the make/model as well as usage, such as the brightness settings. For instance, the Aimpoint Acro C-1 is designed so that, when used with the appropriate batteries, the optic has a battery life of up to 1.5 years when set to 6/10ths of the brightness setting.

Trijicon RM-06. Credit: trijicon.com

Trijicon RMR Adjustable LED RM06 and RM07 models have a battery life of up to 4 years on brightness setting of 4, which is roughly 50 percent illumination. On setting 8 (100 percent illumination) battery life is 25 days. However, Trijicon RMR sights with active illumination usually have a battery-saving feature, which dims brightness after 16 hours of being left on without being used or being in a dark environment. This feature is also found on Trijicon’s SRO red dot as well.

If you anticipate use in dark or low-light environments, battery-illuminated is the better choice, especially if it has an auto-dimming capability to preserve battery life.

Obviously, longer battery life is desired if you’re using the optic on a carry gun, but might not be such a high priority for a range gun.

Leupold DeltaPoint Pro. Credit: Leupold.com

Speaking of batteries, WHERE the battery is located is another feature to be aware of. Some have a battery port that requires the optic be taken off the mounting plate to replace. Others, including Trijicon’s SRO, SIG SAUER’s Romeo 1 and the Leupold DeltaPoint Pro, have top-loading battery compartments…much more convenient and you don’t have to re-zero. Typically, they accept a CR battery such as a CR2302.

Another feature to look at is the field-of-view. The larger the better is the general rule, but again this depends on application. A close quarter weapon or target pistol for run and gun events at close ranges (if competition is your goal) doesn’t necessarily need the largest field of view but should have good visibility. A hunting optic requires the largest field of view possible and therefore the largest optic.

Specs vary between models, so consider what your priorities are carefully. A red dot for a carry gun should be unobtrusive while holstered, so that will mean a smaller overall optic. The model you want for that 10mm long slide or .44 Magnum revolver should be as big as possible.

Consider also your handgun selection. There is no best pistol when it comes to red dot sights, but there are clearly some better choices than others. Most pistol makers offer models that are optics-ready, with very popular choices being the GLOCK MOS models and optic-ready SIG pistols. Smith & Wesson’s CORE models are also optic-ready, including some new models of the uber-popular M&P Shield, arguably the most popular pistol for concealed carry besides maybe the GLOCK 43 and G19.

If you’re considering mounting an optic, there are several ways to go about it if your pistol isn’t already compatible. A mounting plate will have to be installed, but there are a couple of ways to go about it. First is to have a gunsmith machine the slide and install a mounting plate. You can also purchase a slide that has the mounting plate already installed, and have a gunsmith install it instead of the factory slide, unless you feel capable installing the parts yourself.

So…anything you feel I missed? General comments and criticisms? Feel strongly that pineapple really DOES belong on a pizza? Sound off in the comments!

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