How to Zero a Scope – A Step-By-Step Guide

Every shooter must zero in their scope correctly if they expect to achieve high accuracy levels. This post will cover a few different methods on how to zero a scope at 100 yards, without shooting groups, and for a total factory reset.

General Guidelines on How to Zero in a Scope

Zeroing in your scope requires an active awareness of your environment and a functional understanding of the following factors:

MOA: Minute-of-angle (MOA) represents each of the minutes in a 360 circle (each degree is divided into 60 minutes, making 21,600 minutes total). After a few calculations, the MOA equals roughly 1/60 of a degree, making it about 1″ per 100 yards. This dictates the increments you use to adjust the windage and elevation.
Windage: This represents the right and left movement of your aim, and thus, your ammunition. So, imagine that you’ve fired a group, and you were a bit off to the right of the target. In this case, you’ll need to adjust the windage to the left.
Elevation: Your elevation is how far up or down you’re aiming, and therefore, where your rounds travel. Imagine that you just fired a group. Your shots are a bit high. In this case, it is best to adjust your elevation downward for a more accurate shot.

Zeroing in your scope will help ensure that you’re not too far up, down, or to either side by using the correct number of MOA clicks.

As mentioned above, the process varies slightly depending on the type of firearm you have and your preferences (e.g., do you want to zero without shooting, or do you prefer firing groups?). Below are some of the most common ways to sight in a scope.

How to Zero a Rifle Scope at 100 Yards

The most common way to zero a rifle scope at 100 yards is to use a trial-and-error method. This entails an approximate initial adjustment to start things off, then firing groups and making more precise adjustments based on your observations until you’ve got it right.

Follow these steps below to use this style of zeroing in:

Boresight your rifle. To do this, you’ll have to disassemble your rifle to see through the bore (the barrel). This will give you a good idea of where the bullet will land once fired. Here’s how to do it:
- If you have a single-shot rifle, open the action. Shooters with bolt action rifles will need to remove the bolt. (These options should work for most rifles, but firearms with more complex assemblies, like semi-automatics and pump-action rifles, will require more to be taken apart.)
- Draw a large red dot (or another easy-to-see color) where you want to aim at the paper.
- Place the paper target downrange at 100 yards.
- Look through the barrel and center the dot. Now your rifle is boresighted!
Make your initial adjustments. Note whether you are aimed too high or low or are too far off to either left or right. Adjust the windage and elevation as needed.
- Note: Check if your MOA is 1″ per click, ½”, or another measurement. This will determine how many clicks you need to turn the knob for a more accurate shot.
Shoot a group. Now it’s time to put your initial adjustments to the test. Fire a group of either three or five (whichever you prefer) rounds.
Make more precise adjustments. Note where you’re hitting the target. Are you too high, low, left, or right? Adjust the windage and elevation as needed while keeping your target distance in mind.
Repeat until your shots are centered correctly.

How to Zero a Scope Without Firing

You might not always have the opportunity to fire a few rounds as you’re zeroing your scope. (Or you simply may not want to.)

This process shares a few similarities with the one above. The main difference is that you’ll almost certainly need a laser. Without this tool, you’ll have quite a bit of difficulty sighting in without shooting.

Follow these steps below to conserve your ammunition while zeroing in:

1. Place the target at your preferred distance (25 and 100 yards are the most widely recommended). Some suggest getting a bullseye if you want to zero without firing groups. This may make it a bit easier to sight in, but it’s not required.
2. Fix your rifle’s position. You can either set your rifle up on a mount or rest it on sandbags to keep it stable.
3. Install the laser sight. You may need to install it on the barrel’s edge or in the chamber, depending on your gun.
4. Power on the laser and center it on the target or bullseye.
5. Align the reticle with the laser point. Your rifle is now zeroed!

Keep in mind that you may not need to install a laser separately. Lots of scopes come with a built-in laser, but they are often more expensive.

How to Reset a Scope to Factory Zero

A time may come when you need to reset your scope to wipe your slate clean, essentially. You may have gone a bit too far with past adjustments, leading to excessive wear on the scope’s inner components.

If you suspect this is the case, try using the steps below to return your scope to its factory settings before zeroing in again:

1. Remove the pressure from the internal spring by loosening the windage and elevation knobs. Change them to be all the way to the right and up, respectively. You don’t have to count the number of clicks, you can just refer to the numbers on the outside of the knobs.
  - Note: Do this only a few clicks at a time. This will prevent damage to the erector unit.
2. Note the maximum amount of travel per turret and divide that value by two.
3. Adjust the windage and elevation to that value.
4. Now, you can re-zero your scope safely.

Summary

Zeroing your scope is quite easy, even without shooting your weapon. All it takes is a sound understanding of how the windage and elevation work together when adjusted by the current number of clicks per MOA.

Refer to this guide the next time you’re sighting in for accurate shots (especially if you need to factory reset it to prevent excess wear).

Joseph Fox

Joseph Fox writes on a variety of topics ranging from reloading ammunition to gun cleaning. He has been featured on various publications like thetruthaboutguns, Sofrep & many more. Joseph is also the founder of Gunloading, where he reviews different types of reloading & firearm products available on the market.