When throwing horseshoes or hand grenades, centimeters and millimeters are of little concern. But with firearms, these precise measurements may dictate life or death. Competent gun owners know they’re responsible for every round that exits their weapon, and an accurate weapon is a reliable weapon. And to increase efficiency, modern gun owners turn to advanced optics such as red dot sights. But if you don’t know how to zero a red dot, your unpredictable fire may undermine safety.
With zeroed sights, law enforcement officers shoot confidently that their round will neutralize the threat, not an innocent bystander.
But civilians benefit from red dot sights as well.
For example, private homeowners rest assured that their shot will stop intruders, and competition shooters improve their chances of taking first place.
So if you recently purchased a red dot, let’s break down the zeroing process to perfect your weapons’ accuracy.
What is a Zero?
We zero a sight or optic by adjusting the optic so the point of aim equals the point of impact on a target at a specified distance.
If you take a rifle or optic out of a box and fire it, your shots will likely not hit the point at which you aimed.
Of course, if you’re five meters away from a target, you’ll likely hit the bullseye with any weapon.
But as you move farther away, the more gravity and velocity will influence the trajectory of the bullet.
Neither iron sights nor red dots have permanently fixed points of aim, and all shooters must tailor their optics to their individual specifications.
But zeroing is a simple process, and once you know how to sight in a red dot, you’ll understand the concept for all optics.
When we zero an optic at a defined distance, we’re confident the shot will land on target at that range.
Shots may vary with weather conditions, bullet grain, or with added attachments such as a different flash suppressor. But generally speaking, your zero will stay true.
Let’s refer to the graphic below to illustrate.
Note: This graphic is not to scale but depicts how zeroing works. We define this variation with a measurement called “Minute of Angle.”
Trajectory Variation and Minute of Angle
The term sounds complicated, but we’ll simplify this principle enough to know how to zero a red dot.
In short, we use MOA to determine the variation in bullet trajectory within an imaginary cone protruding from the rifle.
The farther the target, the more deviation between where you aim your red dot and where the rounds impact the target.
How to Zero a Red Dot Sight
Before we put rounds downrange, let’s ensure we properly prepare and set expectations.
If you’ve recently purchased your first firearm and researched the subject for any length of time, you likely realized there is a wide preferential range for how to shoot or what to shoot.
Zeroing is a scientific process that won’t change based on opinion, but how we approach it may vary between shooters.
We’ll note these as we come across them, and you may judge what works best for you.
Step 1: Set Distance
In this example, we will zero at 50 yards.
But shooters may zero at other distances depending on the practical application of their rifle.
A 50-yard zero will keep your red dot on point between150 and 300 yards, which is a common distance for home defense.
Hunters or sport shooters that intend on firing at longer distances may zero their weapons differently.
For example, here are a few standard zero distances:
- 25 Yard Zero-This shorter zero length is typical for close-quarters shooters such as military service members or SWAT officers
- 36 Yard Zero- This is a compromise between the 25 and 50-yard zero
- 100 Yard Zero- This long distance is typically for shooters using magnified scopes at far reaches, such as hunters
Step 2: Position
People in the gun community debate whether to zero from a supported or unsupported position.
Firing from an unsupported position introduces potential marksmanship flaws such as poor aim or sight picture.
Since zeroing determines where the round will strike, it’s essential to remove all external variables.
Also, while sitting, you can separate your upper and lower receiver to get a better view through your red dot and see if the reticle appears on the target without the lower receiver obstructing your view.
Shooters who prefer to fire from an unsupported position argue that one should zero how they’ll shoot in real-world situations.
While there’s some truth to that statement, shooters generally recommend firing from a supported position so you can focus on the zero without distraction.
This is especially true if you’re a beginner.
Step 3: Loading
After putting your rifle back together, load a five-round magazine, which brings us to another disputed preference.
Some prefer to zero with only three rounds, but we get a better analysis by firing five-round groups.
With more shots fired, we can rule out marksmanship variables such as breathing or trigger squeeze.
For example, if you fire five rounds and only one is an outlier, you can safely assume deviation resulted from a marksmanship issue
Step 4: Aiming
Now put your red dot on the center target, and turn the reticle brightness down. This way, your red dot won’t obscure the target.
A common misconception with red dots is that it’s necessary to use the iron sights in conjunction with the reticle.
Iron sights and red dots have independent zeroes, so using both sights simultaneously distorts the zero, yielding inconsistent shots.
Also, remember that the purpose of using a red dot is not to have to rely on the iron sights.
However, ensure you can see your iron sights through your red dot in case the red dot becomes inoperable.
Step 5: Initial Fire
With your red dot on the center target, fire your initial 5-round magazine.
Take your time, and focus on your fundamentals to eliminate as many external variables as possible.
Rushing this process can lead to inaccurate shots, and your zero will determine all future shots, so make it count.
Now, let’s use the example below to illustrate your initial fire.
The outlying round to the left is likely due to trigger squeeze since the other rounds grouped well.
It would be harder to see if we only fired three rounds.
Step 6: Make Adjustments
This initial fire is a promising start, assuming you aimed at the center target.
Since we’re hitting the target down and right, we must adjust the red dot sight up and to the left.
As previously mentioned, we must change our Minute Of Angle by adjusting the windage and elevation.
Most sites have elevation modifications on the top and windage on the side and will adapt with a one-click MOA, which equates to roughly .5 inches on target.
But sights vary in click increments, so refer to your device’s product manual to ensure you know how to adjust your red dot sight.
Step 7: Confirmation Fires
After making adjustments, take a comfortable, supported position, and fire your second 5-round magazine.
Let’s use this example to illustrate:
While this is an improvement, we’re still slightly to the right.
At this point, you can fire again to confirm or skip ahead to make additional adjustments.
Once you’re comfortable with your zero, it is best practice to confirm at 150 to 300-yard targets to ensure your zero holds up.
How to Zero a Red Dot without Shooting
Are you looking to speed up the process?
You can take a shortcut with a laser boresight if you want to zero your red dot without firing.
A laser boresight is a device shaped like a standard round that fits into the chamber of your weapon.
The device points a laser onto a target, and the shooter simply adjusts the red dot to match the laser.
These devices are generally inexpensive, and shooters should always verify the weapon’s accuracy with a live-fire afterward.
Advantages of Using a Red Dot
The overall purpose of using a red dot is to improve accuracy, but several other considerations exist.
For example, a red dot sight allows shooters to see in low-light environments.
Trying to view a target in the dark with iron sights is difficult, causing shooters to miss and injure someone else or fail to stop the threat.
Red dot sights also provide an advantage to shooters with less than perfect vision and benefit expert shooters whose eyesight wanes as they age.
But red dots also build confidence in beginner shooters struggling to put rounds on target.
Yet regardless of your proficiency or use case for your rifle, we must learn how to zero a red dot as responsible gun owners.
Failing to adequately maintain your arms and equipment can lead to loss of innocent life or criminal charges if rounds hit an unintended target.
To ensure you hit the mark, visit Meprolight.com for product availability and information on everything you aim for.