Home Scopes & Sights How to Mount, Use, and Zero a Red Dot Sight?

How to Mount, Use, and Zero a Red Dot Sight?

red dots mounted on guns

Red dot sights are very simple optics, and that’s why we love them. They are designed to simplify all aspects of shooting.

They make it quicker and easier to get on target, hit that target, transition between targets, and so on and so forth. But what about all the work prior to shooting?

You have to mount and zero the optic, and knowing how to do that is a key to success. To make sure you are fully prepared, let’s talk about how to properly set up and use your red dot sight.



Mounting Methods

Mounting red dot

Mounting a red dot is the act of connecting the red dot to your weapon of choice. Red dots are very versatile tools and can be mounted to both long guns and handguns with relative ease. There are some differences between mounting methods, but they are all simple.

Mount selection is important. Most red dots come with an integral mount, and about 90 percent have some form of a built-in mounting system.

These systems tend to be very secure and stable, and that’s why their top the choice of most red dot manufacturers. Some companies, like Aimpoint, include a mount but allows you to remove and replace it.

Always choose a high-quality mount from a company known to be reputable.

The most important part of mounting an optic is ensuring it is secure once it’s mounted.

Think about it for a second: as your gun fires and recoils, it’s going to have tons on vibrations going through the system. This can cause things to move and shift. Even a slight bit of looseness can throw off your zero and your shot overall.

Different mounting systems offer different levels of security. QD mounts with levers, for example, are quite secure as-is.

Mounts that require you to tighten the system down via bolts do require some form of thread locker. Use a nonpermanent thread locker, often known as Blue thread locker. This is a must-have when it comes to mounting.

You’ll likely also want to invest in a high-quality set of screwdrivers or Allen keys. You’ll want precision made tools that are non-marring to avoid scratching the finish on your optic.

This is not a must-have, but if you are like me, you want something that won’t scratch your optic or mount. Wheeler Engineering makes an awesome gunsmith set with enough drivers for any application.


For Long Gun

Red dot mounted on long gun

Long guns include shotguns and rifles, as well as AR, AK, and similar pistols that are more rifle-like than handgun-like. These are the more common of platforms rocking red dots and allow you to mount both a dot and a magnifier.

To mount a red dot to a long gun, you are going to need a rail system of some kind. The most common is a Picatinny rail, and outside of some 22LRs and air guns, this is the most universal rail system for mounting any kind of optic to long guns.

A few alternatives exist but are not popular or common enough to mention.

Red dot scopes have unlimited eye relief. This means you can mount nearly anywhere on the gun forward of your cheek weld.

However, just because you can doesn’t mean you should. Modern rifles have rails that extend all the way from the receiver to near the end of the barrel.

I also suggest mounting the red dot to the receiver with modern weapons, the reason being that rails can have some flex or vibrate quite a bit. This can cause your zero to not be less precise than a receiver-mounted optic.

Unless you must mount the optic forward of the receiver, I do not advise it. I understand with take-down weapons, like the Ruger PCC, it can be more precise to mount the optic to the barrel.

In those situations, it makes more sense if you are taking the barrel off the gun often. Otherwise, it’s not always optimal or possible to mount an optic to a receiver.

On the receiver, the optic should be mounted far enough away to be comfortably used. It doesn’t need to be right against the eye, and if you are using a magnifier, you may be forced to mount the optic near the front of the receiver to make room, which is perfectly fine.

Once you select the location you should tighten the optic down. If it’s a two-screw base, alternate tightening on each screw. Once the optic is mounted and you can comfortably aim through the optic, go ahead and apply thread locker.

You can take the optic off and apply thread locker if that’s easier. Just note where you removed the optic from. Thread locker takes some time to dry, so allow it to dry before zeroing.


For Handgun

red dot mounted on hand gun

Mounting a red dot to a handgun is a little harder. You have multiple options to mount the optic, and this requires a special system for each situation. In general, you can only mount the optic in a single place, depending on the mounting system you choose.




Milling your slide to accommodate the footprint of your chosen optic is the most common method. This involves sending the optic to a gunsmith and having them do the heavy lifting.

All you need to do is align the optic, apply thread locker to the screws, and secure the optic to the slide.

This is the most expensive method, but it is also the most secure.


Rear Sight Replacement

Some optics offer a mounting plate that replaces your rear sight. I know Burris and SIG both offer these systems for a variety of handguns. This is something you can do at home cheaply with a rear sight pusher.

This system works but adds height to the optic and is not as secure as milling. You have to attach a rear sight block, the plate to the block, and then the optic to the plate. Make sure you apply thread locker for every screw.



ZeroingZeroing is the process of taking your optic and aligning it so your rounds strike the target. With red dots, it’s a very simple process.

You can use any target you’d like, but targets designed for zeroing with a grid square backgrounds are exceptionally handy. There are even specific red dot zeroing targets out there.

1. The first step is knowing your weapon. Red dots work on any gun really, from rifles to handguns, and even crossbows. However, you have different expectations for different weapons.

You wouldn’t zero a red dot for a rifle the same way you’d zero a shotgun. You must zero the dots at different distances.

A shotgun red dot should be zeroed at 25 yards for buckshot and 50 yards for slugs.

A modern sporting rifle, like the AR-15, should be zeroed at 50 yards. The zero at 50 yards will take you out to 200 yards effectively.

Handguns can be zeroed out to 25 yards, and good shots can push it out to 50 yards. Twenty-five yards is standard though.


zeroing hand gun red dot

I typically start closer than the above distances. I’ll do a quick 15-yard shoot to make my major adjustments. This will ensure I am at least on target and on paper before backing up further.

This is incredibly important with a handgun since they are more challenging to shoot.

Red dots are equipped with an elevation and windage point to adjust. Typically, the elevation is on the top of an optic, and the windage is on the side.

However, some miniature red dots put these adjustment points together. Consult your manual to ensure you know where the elevation and windage adjustments work on your optic.

These dials work in MOA measurements on 99 percent of red dots. Each click of the dial represents an adjustment.

MOA represents one inch at 100 yards. Most red dots adjust in ¼-MOA increments per click. So, at 100 yards, one click is a ¼ inch of movement up, down, left, or right depending on the dial.

2. Load up three rounds into your rifle or long gun. Assume a well-supported position, either prone or using a table to support you.

3. Fire the three shots and observe where they strike their target. From here you need to make your adjustments.

Let’s say you hit low and to the left. At this range, you are just making broad adjustments, so you want to simply dial the optic to the right and up and then fire again. If you are consistently on paper and near the target, you are good here.

4. Once you are on paper you can back out to 25 yards with the pistol and shotgun and refine your zero. If you’d like, you can also stop at the 25 yards to ensure your rifle optic is still solid before going back to 50 yards.

At this range, we are making fine-tuned adjustments. At 25 yards, a ¼-MOA adjustment is only 1/16th of an inch. It’s a very small adjustment at this range, so you can use half or quarter turns to speed things up.

5. Fire your three shots, observe, and then rotate the dials an approximate amount of space. Fire again, adjust, and continue until you are hitting exactly where you are aiming.

With a rifle, you can move back to 50 yards. (Remember: A ¼ MOA turn here is ⅛ of an inch.) Repeat the above process until you are striking your target. Once your weapon is zeroed, fire three more rounds and confirm you are zeroed.


Using Red Dots

using red dots

Red dots are very easy to use. First, you focus on your target and bring the red dot to your vision. You focus on the target and allow the red dot to rest on it.

With a red dot, you shoot with both eyes opened, and the red dot superimposes itself over your vision.

Red dot intensity varies depending on external conditions. The brighter it is outside, the brighter you want your dot. The darker it is, the dimmer you want the dot.

Running a bright dot in a dim environment can be painful and cause your dot to blur, making it difficult to see through your optic. If the dot is too dim in a bright environment, then you simply won’t see it.

Red dots are quick and easy to use and perfect for new and old school shooters. They are faster than iron sights and often more precise.

Knowing how to use a red dot sight is the key to your personal success with red dots. As always, consult your manual as well. I hope you folks learned something, and if you have any questions, ask below.


  1. I have a question… if you use “lock tight”, what happens when you need to replace the batteries on the sight? This is an issue I’m having with my hell at pistol. No matter how much I tighten the screws, after only a few rounds they become loose. Any suggestions would be greatly appreciated!!!!



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    • It depends on which threadlocker you use. Blue Loctite isn’t too strong so it’s still easy to remove the screw by hand. Red Loctite requires heat to remove. Most people touch the screw with a soldering iron for a few seconds to break the seal. I’ve also heard of Vibra-Tite VC3, which is supposed to be like blue Loctite but doesn’t have to be reapplied every time.

      Happy shooting!


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