How to Mount a Red Dot Magnifier

A red dot sight magnifier is an optical accessory that allows you to instantly increase the magnification of your optic to acquire long-range targets. This versatility lets you adapt to dynamic target ranges with ease using a flip-up mechanism, making red dot magnifiers an excellent accessory for 3-gun runners and tactical operators. If you don’t already own one, our Guide to Red Dot Magnifiers offers an in-depth explanation of what they are and the benefits they provide. For those who purchased a magnifier and are looking for clarity on how to properly mount it, this guide is for you.

Does the Magnifier Go Before or After the Red Dot Sight?

While this seems like a straightforward question, there is often a lot of confusion about what order to place the optics and why. The correct mounting setup is:

Your Eyes > Magnifier > Red Dot Sight > Barrel

This mounting method ensures you magnify the red dot sight image instead of the red dot itself. If you mounted the magnifier in front of the red dot, you would be magnifying the red dot hardware, not the image. This may result in blurry, unusable reticles, and the MOA dot would scale incorrectly relative to your target.

With the correct mounting setup above, the dot stays centered and delivers a clear, unobstructed sight picture. The most important reason to mount it this way is eye relief, which is the optimal distance between your eye and the lens of an optic. Most red dots have virtually unlimited eye relief, but all red dot magnifiers have limited eye relief, usually around 2-3 inches. This means that the red dot optic can technically go anywhere on your rail, but the magnifier needs to be close to you to suit the eye relief requirements.

Other Mounting Considerations

Rail Space

With eye relief in mind, you need to ensure you have plenty of rail space to optimally mount both optics. Make sure to check the manufacturer specifications for the exact length of the magnifier before purchase to ensure it fits your setup.

Distance Between Red Dot and Magnifier

Ideally, you want both optics as close as possible to optimize rail space and balance the weight towards you rather than the front of the firearm. You only need to leave enough space between the red dot and magnifier so that you can properly employ the flip-up mechanism.

Mount the Optics on Your Upper – Not the Handguard

You should always mount the red dot magnifier combo directly on your upper receiver, not the handguard. During fire, your handguard experiences more movement and vibration from recoil than the upper, which puts your red dot’s zero and mounting stability at risk. Also, the barrel may generate enough heat to compromise the integrity of your optics, so keeping them further back prevents thermal distortion.

Even if your optic is incredibly durable, placing it at the front of the firearm makes it much more prone to damage. Whether you’re a tactical operator clearing rooms or a civilian transporting gear to the range, you’re much more likely to bang up the front of your gun than the rear side towards you.

Achieving Proper Co-Witness & Alignment

Co-witness refers to the process of properly aligning the reticle of the red dot sight with the center of the magnifier so that your point of aim and point of impact are in sync. With proper co-witness, you can flip-up or disengage the magnifier while maintaining peak accuracy with either setup. After mounting the optics at your preferred height, adjust the magnifier’s windage and elevation knobs until your red dot reticle is centered. Make sure to test your view with and without the magnifier to confirm consistent alignment.

Zero Your Red Dot Sight

With all the optics in place, the final step is to zero your red dot scope. Since the magnifier doesn’t have a reticle, it doesn’t have to be zeroed. With the proper co-witness in place, zeroing your red dot will certify that both components are in harmony, ensuring the point of aim and point of impact are not only aligned, but true. To do this:

• Secure your AR in a stable shooting position using a bipod, bench rest, or sandbags.
• Set your target This depends on your rifle, shooting style, and ammo choice, but the most common options are 25 yards, 36 yards, and 50 yards. If you’re experienced, you should already know your preferred zero. For beginners, a 50-yard zero is the most popular and forgiving option.
• Aim at the bullseye and fire a few shots. From here, you just need to adjust the windage (which moves point of aim/impact left or right) and elevation (up or down) on the red dot until you consistently land shots on the center of the target.

Once your red dot is properly zeroed, test some more shots using just the red dot sight and with the magnifier engaged to ensure everything is running smoothly. If your zero with just the red dot is perfect but the magnifier is misaligned, your co-witness is most likely off. In that case, just keep fine-tuning the windage and elevation knobs on the magnifier itself until you’re nailing that target center every time.

For a more in-depth look at this, check out our guide on 4 Easy Steps to Zero & Adjust a Rifle Scope. While the distances are focused on rifle scopes, the same principles apply to red dot sights.

Get Pure Precision with Proper Placement

Red dot magnifiers are versatile tools for marksman who need to tackle a variety of target ranges with the same firearm and ammunition. With a high-quality red dot magnifier combo and the right mounting equipment, you can dominate targets near and far without switching platforms. Hopefully, this guide helped you figure out the correct way to mount your red dot optic and magnifier and why you should do so. Check out all our red dot sights and accessories for sale to find the best deals on premium optic upgrades and mounts and risers to put everything into place.