Introduction
Zeroing your scope is a vital skill for any shooter to adjust their scope to their rifle. Whether you're trying to get the most out of a new rifle or adjusting your ammo type where your point of impact may shift, you need to know how to zero your scope on your rifle.
Zeroing a scope ensures that the point of aim with your scope matches the point of impact on your target at a determined distance (100 yards or 100m is common). This is the key to getting your rifle to shoot accurately and being efficient with your ammunition.
Related Article - scope Features when Shooting at Phoenix Rifle Club
Setting the Zero
Zeroing your scope on a rifle is the process of adjusting it so that your point of aim matches your weapon's point of impact at a given distance. It's important to do this accurately, as it will improve your shooting accuracy.
The first step is to make sure that your scope is installed correctly on the gun and that the rings and bolts connect securely to the base of the mount. Use the correct torque specification on the rings and the mounts. Several factors can affect the zeroing of your scope, including the quality of your ammo.
Ammo is important because different bullets have different rates of drop, which can influence your point of aim. Hunters should stick to one type of ammo and shoot with that type for all their shots because changing ammo will change your zero. For target shooters, reloading might be worth exploring to tighten the groups, or good premium ammo might be the solution for a reliably repeatable shot.
Another factor that can affect your zero is the wind. The faster the wind blows, the bigger the deviation and inconsistency of your shooting, which can cause them to drop, shift sideways and even lift. Using bullet trajectory tables and charts, or even a Kestrel Ballistic calculator is a good way to compensate for this. But for setting your zero - ideally, you don't want any wind conditions.
You also want to have adequate eye relief on your scope. This will prevent your reticle from hitting you when the weapon recoils. Ensure you have at least 3.5 inches of eye relief on your scope.
Some scopes have a parallax adjustment turret. This is a third turret knob that adjusts for the reticles' tendency to shift with the movement of your head - bringing the reticle and the sight picture in the same plane. Parallax is usually located on the left or the front of your scope.
Parallax on low-quality scopes can be a serious problem, especially for newer ones. It can lead to blurry images, missed shots, and just frustration to be able to get on target. It's best to avoid it as much as possible by purchasing a scope with high-quality turrets and decent glass.
Lastly, you should always use a gun vice to keep your gun stable during the zeroing process. This will help to reduce the chances of human error and can save you a lot of time, money, and wasted ammo. Gun vices however need to be used in a limited fashion as the recoil tends to whiplash the rifle and can damage the scope over repeated use.
The next step is to fire three rounds at a target, observing the point of impact on the target and adjusting the windage and elevation turrets as needed. Once you have a satisfactory zero, the rifle your scope might have a zero-stop to set. Some hunting scopes you just put the cap back on, and it is ready to go out hunting with. Some hunting zero's are done at 150 yards since the game might be a bit further on average.
MOA (Minute Of Angle)
The first step to zeroing your scope is understanding the difference between MOA and Milliradians. Both units of measurement are derived from the angle of a bullet traveling from the muzzle to a target, but MOA and Mil are different in a number of ways.

Using the wrong unit of measure can lead to inaccurate adjustments, or simply make it impossible for you to make them at all! This is especially true if you are using a scope that doesn’t adjust in MOA or Mil increments.
One of the easiest ways to zero a rifle scope is to use a target with markings in those two units. These targets will let you know how many squares up/down and left/right you are from the bullseye, so that you can make an adjustment to get your zero in line.
Another way to zero your scope is to use a bulls-eye target specifically designed for zeroing. These targets are usually marked with a grid that lets you determine how many squares you’re off from the bullseye in each direction. Once you have a number of squares, turn on your scope and move the reticle until it hits the middle of the grid - all the while NOT moving the rifle in any way. This should be your new zero. You can then confirm your zero with a follow-up shot.
Next, loosen the turret cover and turn it to set your scope’s turrets back to their zeroed position. This will allow you to return to your new zero later should you need to dial in for any reason.
If you’re not sure how to do this, check your scope’s user manual or online. You can also find an image of your scope’s reticle subtension increment on the manufacturer’s website, which is useful for knowing what values you should be using when adjusting the reticle. **********
Milliradians or Mils
Zeroing your rifle scope means that the reticle or crosshairs (what you use to aim) is positioned so that it matches your point of aim at a specific distance. Milliradians is another angle-to-distance measure of like Minutes of Angle, but in a metric way.

There are a few different ways to zero your rifle, but the most common is to simply move the crosshairs until they match the bullet's point of impact. The process is called sighting in, and it's a great way to get your rifle dialed in quickly.
Before you start sighting in, take your rifle out to the range and mount it on a bench with a good rest. This is important, as it will help you maintain your balance and keep your rifle from moving during the sighting in process.
Next, you need to shoot a series of groups of three or more rounds at a 100-yard or 100m target. This should be done using a firm rest, such as a bipod or a shooting bench.
Once you've fired your first three groups, you can now measure how much adjustment your rifle scope needs to bring the center of the group into line with the bullseye. Usually this will be a simple calculation, based on the number of squares up and down and left and right you are off from the bullseye.
If you're a new shooter, or are just starting out with optics, this is a great way to learn the basics of sighting in your rifle and getting it zeroed for a given target. It's also a fantastic way to see how your scope is doing at different distances.
The process of zeroing your rifle scope depends on many factors, but the most important ones are the distance you plan to shoot and what ammunition you'll be using. Most rifles can be zeroed at 100 yards, but if you're going to shoot farther downrange than that, it's better to zero your rifle for a longer distance.
MOA vs. MILs
MOA usually provides a smaller subtension increment than in Mils - 1/4 MOA are smaller adjustments than 0.1Mils. So when it comes to small adjustments in getting your rifle to precisely reach your point of impact with your point of aim (centre of your crosshairs), the 1/4MOA adjustment scopes that have repeatable turrets, will be your best option. However, in the likes of PRS, where rapid calculations are needed, MILs are easier to deal with than MOA (for mental maths). With Ballistic calculators, either one is as easy to read from the calculator screen and to dial in. Especially if you have a HUD (Heads Up Display) that reads it out to you.
Sub-tensions
A scope's reticle contains subdivisions (sub-tensions) that help you make accurate adjustments. These are based on the distance (yards) you need to move your target's point of impact up or down a vertical line and left or right a horizontal one.
The best way to zero your scope is to use a bulls-eye target specifically suited for this purpose. These targets have a lot of measurements and are typically the most precise you can buy.
You can also use a turret-generated elevation click to aid in the zero setting process. This is a feature on all high-end riflescopes, and it's a good thing, too, because it helps reduce movement during the reticle adjustment process.
When zeroing a scope, you want to position the rifle as low and stable as possible. This is important because the rifle's movement will affect the sight picture and can lead to missed shots.
This is especially true if you're using an expensive riflescope with a high magnification. The erector tube and crosshairs will move around quite a bit when you move your aim point, so it's important to have a steady hand.
Taking a little time to set up the reticle correctly will pay off in the long run. It can also improve accuracy when you are actually shooting the rifle with the scope.
You can also get sub-tensions from a scope's crosshairs, but these are rarely as accurate as those from the reticle. This is because the crosshairs are often too thin for the reticle to be visible or they're not placed in an erector tube well enough to be seen clearly.
Scopes
Getting a quality scope is a core component to your firearm - must be recoil tested and endure the likes of a 50-cal, it must resist internal condensation by being nitrogen filled, and a decent set of glass. The likes of Element Optics have had a strong track record for air rifles as well as firearms - in both best value for the money. If you would like to discuss reticle types, scope features, and the application to the rifle type, feel free to reach out to us at the range.