It’s an exciting time, your new scope just came in, and you are ready to mount it and sight it in. Although sighting in a scope is not trivial work, there is a bit that goes into it, and you don’t want to get it wrong.
Whether you have never sighted in a scope before, or if you just need a few tips, today we are going to go over the whole process step by step. Let’s start by quickly defining some of the terms you will see in this article so that you know exactly what I am talking about.
Basic Terms and Important Information
Before we jump right into how to sight in your scope, I am going to review a little bit of vocabulary. If you have done this before, feel free to skip ahead. However, I think this will be very beneficial for newcomers.
A bore sight is a laser sight inserted into your barrel in several ways that projects a laser out of your barrel. You can then adjust your scope to match up with the laser on a nearby target. Ideally, this gets your scope close to sighted in without ever shooting it.
A Minute of Angle is an angular measurement. An MOA is 1/60th of a degree. 1 MOA is about a 1 inch circle per 100 yards. ( actually 1.047 inches) 1 MOA becomes larger at farther distances. 1 MOA at 200 yards is a 2-inch circle, at 300 yards is a 3-inch circle, etc.
Mil or MRAD is a shortened term for Milliradian. A milliradian is an angular measurement that is 1/1000th of a radian. A radian is a portion of the distance traveled around a circle. This is the metric dual of MOA, and MILS are the unit that the United States Military uses for their optics.
Windage is an adjustment you can make to your scope. Windage controls the X axis, or left to right positions of your crosshairs. This is the knob located on the side of your optic.
Elevation is an adjustment you can make to your scope. Elevation controls the Y axis, or up and down, position of your crosshairs. This is the knob located on top of your optic.
A group refers to a number of shots fired. If you shoot three cartridges from your rifle and go check your target, that is a three-shot group. Your grouping refers to how close together the shots in your group are. There is no set number for a group. Your group can be 2, 3, 4, 5 or even 10 shots if you like. However, the most popular and ammo-efficient group is a three-shot group.
MOA vs. MILS
Before you buy a scope, you will need to decide if you want to work on MOA or MILS. MOA is the standard or imperial unit for angular measurement. On the other hand, MILS is the metric unit for angular measurement, which is what the US military uses on all of their rifles. Scopes only come in one or the other, so you will need to decide early on which one is best for you.
Technically, MILS is ever so slightly more accurate than MOA, but that difference will never be seen by even the best of shooters. The other factor that comes into play is that if you use MILS, you also need to measure distances in meters. That is not normal for most of us, so it can be a tough adjustment for most.
What is Zero?
Unlike the terms above, “zero” needs a little more explanation. The term “zero” is used to describe the range that your scope is sighted in at. As a bullet flies through the air, it rises and falls.
Your zero point is set so that you know exactly where the bullet is going to hit (adjusted for drop) every time. Your zero point can be just about anything you want it to be, and you will sight your scope in at the zero point. Saying a scope is “zeroed” is the same as saying it is sighted in.
Understanding Bullet Rise and Drop
When you fire a round out of your rifle, you would think that it comes out flat and starts to fall down gradually. However, that is not entirely true. The barrel of your rifle is tilted ever so slightly upwards. This sends the bullet upwards and counteracts some of the drop we see at longer ranges.
This is why you will hit a target high at 25 or so yards, because the bullet is still rising. If you have ever heard the phrase “zero at 50 means zero at 200” that refers to zeroing the rifle on 50 yards when the bullet is still rising, and that zero being in the same place once the bullet hits its peak and starts to fall back down. When it crosses 200 yards, it is ideally at the same level it was at for 50 yards. The yardage all depends on your caliber and speed of your bullet, so don’t get too hung up on 50 and 200.
Different Ways to Zero a Scope
Alright, now that we got all that out of the way, let’s start sighting that scope in. There is pretty much one way to zero in a scope, but you can also use some other tech to help you do it without shooting. We are going to go over both methods here and show you how to do them.
For the no-tech method, we are going to keep things super simple. You are going to mount the scope, pick a zero, and shoot a group. Once you figure out where your groups are going, you can adjust your windage and elevation as needed. Then you just shoot another group and adjust your scope if needed. Repeat as necessary.
The low-tech method is a lot like the no-tech method, except we will use a bore sight. A bore sight is a useful tool for getting your scope pretty close to dead on without ever shooting it. This is going to save your ammo when you are at the range, which saves money. The cost of the bore sight will offset that cost in the short term, but over the years, it can pay for itself.
Steps to Zero a Scope
Now you have a brief overview of what it takes to sight in or zero a scope. Truth be told, it is not an overly complicated process. However, each step in the process has a little nuance to it. In this section, I will talk about each step in detail so you will know absolutely everything you need to know to make the perfect shot.
Mount Your Scope Securely
The first, and most important step, is to mount your scope securely. This is by far the most important step. If your scope is not mounted correctly, it will move around, and all the work you do sighting it in will be worthless. You also want to make sure that you are using the correct scope mounts. If you are using a scope mount that doesn’t fit right, you could run into problems down the road.
Use A Bore Sight
Once you have your scope mounted, you are ready to sight it in! Although before you go to the range, you could get most of the work done at home with a bore sight. A bore sight is a simple laser that shines through your barrel and onto a nearby target.
You then look through your scope and line up your reticle with where the laser is hitting the target. This will get you fairly close to zero, but you will still need to make some adjustments in the field.
Bore sights come in all shapes and sizes. You can most commonly get a bore sight that simply inserts into the end of your rifle. This kind of bore sight is better suited to be used on a range of weapons. However, you can also get bore sights in the shape of a cartridge and designed to be chambered like a live round. This gives you a slightly more accurate zero with the bore sight, but it is limited to a single caliber.
Pick Your Zero
Picking your zero point is a lot more complicated than just going with 100 yards by default. For some people, 100 yards may work as a zero, but for most it isn’t the best option. Your zero point depends on what your main purpose is with your rifle and the caliber and specific cartridge you use most.
If you are using your new scope on an eastern hunting rifle, you will likely never shoot farther than 300 yards. This means you do not really have to worry about a long zero. The next thing to consider is what caliber you are shooting. It is no surprise that some calibers shoot much farther than others. So a 6.5 Creedmoor is going to be better with a longer zero compared to a 30-06.
So do a little research and pick your zero distance based on your caliber. If you are shooting long ranges, like 500 yards plus, then it would make sense for your zero to be much farther out, around 400 yards or more. It heavily depends on your purpose. Long story short, you want to make your zero distance the distance you will most commonly shoot at, which works best with your caliber.
Shoot Your Groups
Now that you have your scope mounted, bore sighted, and picked out your zero distance, it is time to go to the range! You want to take your time when you are shooting your groups. They need to be as accurate and precise as possible.
I like to shoot three shot groups when I am sighting in a scope. This gives you a good idea of where your shots are going while not wasting too much ammo.
Use a Stable Support
To do that, you want to make sure you are shooting from stable support. A rifle sled is often the best tool to use in this situation, but you can also get a good shot off from a sandbag on a table or something similar.
When you are shooting, just make sure to take your time. Breathe, and slowly squeeze your trigger. You do not want to go making adjustments to your scope just because you had bad form. That is not going to help.
Adjusting Windage & Elevation
Once you shoot your first group, it is time to inspect it. Try to find the center point of your group, and then measure how far away that is from the center of the target.
You will then need to calculate how many clicks you will need to make to adjust for that change. That number of clicks depends on your zero distance and your scope. However, most scopes equate one click to one MOA. So if you are zeroed at 100 yards and you are three inches to the right, you can make a three-click adjustment to the left.
The same can be said for elevation. Although some scopes come with a 0 or 20 MOA base. If you are hunting, you don’t need to worry about a 20 MOA base. However, if you are shooting long ranges, a 20 MOA base will basically give you an extra 20 MOA worth of elevation to work with.
This keeps you from bottoming out your elevation while trying to shoot at 600 or 700 yards. So if you are a long-range shooter and have problems with your elevation, you need a 20 MOA base.
Repeat Until You’re Dialed in
After you shoot your first group and adjust your windage and elevation, shoot again! Repeat this process as needed until you are dialed in. You don’t want to shoot too much, though. If you are trying to save on ammo, your zero does not have to be absolutely perfect.
Your barrel will also heat up if you shoot a handful of rounds in succession. That can change the way your rifle shoots. So take your time in between groups, and let your barrel cool down.
Check Your Zero & Gear Over Time
After you get all of that figured out, you need to check it over time. I always like to shoot a group with my hunting rifle every year before the season starts to make sure I am still on target. Oftentimes, I need to make an adjustment.
I didn’t do anything wrong or drop my scope, but your scope can get a little off every now and then. So it is best to periodically check your zero, as well as your scope mounts.
Sighting in Your Scope FAQs
What Magnification Do You Zero a Scope On?
The magnification level on your scope does not matter while you are sighting it in. Magnification will not change your point of impact. Use whatever level of magnification you are most comfortable with from your given zero distance.
What Should I Do if the Scope Is Shooting Low?
If your scope is maxed out on elevation and you are still shooting low, something is wrong. Something like this should only happen at long ranges, at least 500+ yards. This likely comes from using a 0 MOA base, when you need a 20 MOA base.
What Does It Mean to Zero in a Scope?
To zero in a scope simply means to sight it in at a specific distance. Your zero distance is any distance you choose to sight a scope in. This is the distance that you will be the most accurate in, and the distance that your dope charts will be based on.
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