One-times magnification per 100 yards is an old rule of thumb for magnification that works for many people who need to see things from far away. So, if you’re a hunter shooting at a target 300 yards away, you want at least a 3x optic.
Red dots, however, are unmagnified. That’s 1x magnification!
Red dot magnifiers are a popular tool for increasing the versatility of your reflex sight or holographic sight by giving you enough magnification to shoot your gun at 200 or 300 yards, or even at a greater distance.
Red dot sights may be faster than iron sights and more intuitive, but they don’t do anything to help you engage targets at ranges past what you can shoot with iron sights.
Installing a magnifier behind your optic seems easy to do, but there are ways to mess it up.
Should You Magnify Your Red Dot Sight?
The first question you should ask yourself is whether you should even magnify your red dot sight in the first place.
That’s because every magnifier has several disadvantages.
Namely, most magnifiers weigh about 10 to 12 ounces, which is a fairly significant amount of weight to add to your gun. This can be obnoxious during long hunts and can also throw off the balance of your gun.
Also, magnifiers are bulky. They take up multiple inches of rail space, so you may have to move your optic forward. The tube can extend rear enough to interfere with backup iron sights, so you may have to choose between one or the other.
Magnifiers magnify the reticle of most red dots too. Three-times magnification will turn a 2 MOA dot into a 6 MOA dot and a 3 MOA dot into a 9 MOA dot! Clearly, magnifiers are not exactly precision instruments.
The exception is if you use them with holographic sights, which use a laser instead of an LED. Holo sight dots work differently than reflex sights, with the result that 1 MOA dot stays 1 MOA no matter how much you magnify the sight.
However, adding a magnifier does allow you to swap between an unmagnified view and a magnified view of your target so you can choose between speed and precision.
If this sounds like a good idea to you, then consider low-powered variable optic scopes, which are a lightweight option for having both unmagnified and magnified sights.
Note, though, that LPVO scopes rarely have a true 1x zoom, and the reticle isn’t quite as fast or parallax-free as a red dot sight.
Picking the Right Red Dot Magnifier
If you still want a red dot magnifier, then it’s a good idea to pick out a good one.
Thankfully, even cheap magnifiers are fairly durable. There is no reticle to knock around. Cheap mounts, however, can fail, and cheap lenses won’t transmit much light.
And since the light reflected off the target will have to travel through both your sight and your magnifier, light transmission can be a problem.
I’d recommend getting a 3x magnifier with a long eye relief, because that tends to be the most annoying part of using a magnifier, in my experience. Holosun and Vortex make high-value magnifiers, while EOTech and Aimpoint make the most durable magnifiers.
How to Install a Red Dot Magnifier
Most red dot magnifiers either come with a quick-detach mount or have one built in. Some don’t come with a mount at all, and you have to add your own. I highly recommend getting a QD mount.
You’ll also need to align the magnifier’s height with your red dot sight’s height.
If you have an AR-15, your red dot sight will either have absolute co-witness with the iron sights or will have lower one-third co-witness. Some magnifiers are tall enough that they can only work with lower one-third co-witnessing optics. Shorter magnifiers may come with risers so you can use them with both.
Next, decide which side you want the magnifier to flip toward. Most flip toward the right, though this can occasionally be interrupted by the AR-15’s forward assist.
Most, but not all, magnifiers can switch around the mount to facilitate both left-handed and right-handed flipping. Use whichever side feels more comfortable to you.
Now it’s time to put the magnifier onto the rail.
If you have a QD mount, then it has a lever with adjustable tension. Start off with loose tension for now because you may end up moving the magnifier back and forth.
The front of the magnifier should be as close to the rear of the red dot sight as possible. The rear of the magnifier should be far enough back for you to comfortable look through the lens without having to move your head off of your normal cheek weld.
The rear of the magnifier may hang over a flip-up iron sight. If you can position the magnifier so you can flip up the rear sight when the magnifier is to the side, then you’re lucky. Most of the time, you’ll have to remove the magnifier to use the rear sight.
Test your firearm’s balance with the magnifier installed and move it forward or backward until you’re all around happy.
Now it’s time to adjust the QD lever’s tension.
Typically, this involves pulling the lever halfway and tightening a set screw. Push the lever down so it locks in place and try to move the magnifier around. Your goal is to get the QD lever tight enough that the magnifier doesn’t move but not tight enough to risk damaging any components when you lock the lever.
Congratulations! You’ve installed your red dot sight.
How to Use a Red Dot Magnifier
First of all, you need a sighted-in red dot sight.
If your sight is already sighted in, then it’s time to adjust the magnifier.
There are typically three adjustments: diopter, elevation, and windage. The latter two are sometimes called azimuth adjustments.
The diopter adjustment is the focus ring, generally on the rear of the magnifier. You rotate this ring while looking through the sight at an object 100 yards away until the view is as crisp as possible.
The elevation and windage adjustments require a tool (typically an Allen wrench) on cheaper models and no tool on more expensive models. You want to adjust these until the red dot’s reticle is in the center of the magnifier.
This doesn’t actually affect where your gun shoots. It does, however, minimize any potential parallax errors from misalignment between your eye, the reticle, and the target.
Now all you have to do is go shooting!
Keep the magnifier up when you want to shoot at longer ranges. Lower the magnifier for shooting at 100 yards or closer and when your goal is speed, not precision.
Red dot magnifiers are not the perfect tool for every occasion.
However, they do increase the versatility of holo sights and reflex sights.
Though they add weight to your gun, many people like to keep a flip-to-side magnifier on the rifle they use for competition, hunting, or combat.
They’re easy to install and use. The hardest part of using a red dot magnifier is choosing which one to buy!