How to Zero a Rifle Scope

Throughout your shooting career, you’ll find that you will need to “zero” your rifle scope. Zeroing a rifle scope is the act of aligning the scope or optic with the barrel so that the crosshairs match where the bullet is going to fall. There are many occasions where you may need to zero your rifle, so it’s an important skill to have – such as after long term storage, adding a new scope, a hard knock or simply changing ammunition types.

In today’s guide, we’re going to go through the steps for you so that you know exactly how to make your rifle as accurate as it should be.
 

1.Find a safe area to shoot

Zeroing your rifle will require you to shoot your rifle. Naturally you’ll need to be in a controlled environment, so that you can be safe when doing so. Your local range is a good place to do zeroing. However, ensure that you are set-up in a way that means you don’t have to call a cease fire and apply a new target after every shot as this can be frustrating for other shooters. This often means steel shooting steel or multiple targets already set-up.

Here, it’s really helpful to be familiar with the target. That is, to know the distance between markings and zones within the target itself.
 

2.Remove human error

Human error is a huge contributor to inaccuracy and you want to remove this aspect when zeroing. Otherwise, how will you know whether your rifle is inaccurate or you are? This is commonly done by setting the rifle up in a vice, on a bench or on sandbags to remove as much error as possible. This allows you to be more consistent with your shots.

You’ll also want to be set up at a known distance from the target. This is often 100 yards but use a distance that you’re most likely to be shooting at. Also ensure that you’re shooting directly towards the target, not at an angle, as it may affect your adjustments.
 

3.Understand how to adjust your scope

It’s relatively obvious how to adjust your scope. There will be a dial on the side for left-to-right adjustment and one on the top for up-and-down adjustment.

However, it’s equally important to understand what these adjustments mean. How many clicks of the dial will bring your site on target?

Most scopes have these adjustments labelled on them – usually, MOA. This indicates the distance the crosshair will move on the target with one click of the dial.

MOA stands for “minute of angle”. Adjusting the scope by 1 MOA adjusts the scope by 1 inch on the target if it’s 100 yards away. Obviously, 1 inch is a large movement on the target, so this is then further broken down into quarters.

1 click on a scope is (traditionally) ¼ MOA and results in a smaller change of ¼ inch at 100yards. Alternatively, some scopes skip using “MOA” and simply label it as “1 click = ¼” at 100y” for clarity.

It’s important to note that these adjustments are multiplied by the range you’re shooting at. An adjustment of 1 MOA at 100 yards for 1inch is an adjustment of 8inches at 800 yards.
 

4.Shoot at the target

Align your crosshairs with the centre of the target and fire one round. This is your starting point for how to adjust your scope moving forward.

If you’re unlucky, you’re going to need to make much larger adjustments. This can be done by putting small shims on the correlating side of the scope, or simply loosening the scope mounts and re-tightening whilst moving the scope in that direction. This is because you don’t want to use up all of the adjustment in the scope simply getting the scope to point close to accurate. This would hinder you in future making adjustments for elevation and windage.

If you’re lucky or once you’ve done the above, you only need to make a small adjustment. Using the knowledge you have of your target (being able to estimate the distance from the impact point to the bullseye) you can adjust your scope to reflect the necessary changes.
 

5.Adjust your scope

Using what we’ve just learnt about MOA adjustments, we can take the test shot and calculate pretty effectively, how many clicks to adjust the scope by in each direction.

Example: We’re set up 100yards away from the target and aiming in the centre of the target. We take a test shot towards the target and discover that the shot has fallen 1.5 inches too low and 3 inches to the left of the bullseye.

How we correct this: We know that 1 MOA at 100 yards results in a 1 inch change in our aim and our scope adjusts in ¼ MOA increments.  

Since we need to adjust 1.5inches up, we twist the top dial 6 clicks in the “up” direction.

Since we need to adjust 3 inches to the right, we twist the side dial 12 clicks in the “right” direction.
 

Read 'What is Scope Parallax? and How to Correct it.

6.Rinse and Repeat

Don’t actually rinse.

Take another test shot and see how accurate your weapon now is. You should be pretty close to accurate but there’s always something which can affect the results. Repeat these steps as many times as necessary until you’re completely happy with the results.