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How to Zero a Rifle Scope at 100 Yards

If you are into hunting or sports shooting, you probably know a thing or two about zeroing in your rifle scope. It helps improve your accuracy at a decent range of shooting. You can zero in your rifle scopes at different distances but the best range to get started is 100 yards.

How to Zero a Rifle Scope at 100 Yards

The process of zeroing in the rifle is quite easy and straightforward. In this blog, we will cover we will review how to zero a rifle scope at 100 yards distance.

What Does It Mean To Zero a Rifle Scope

Before we go over the process, let’s clarify what zeroing a rifle scope means. Zeroing is the process of adjusting your rifle’s scope so that the crosshair is centered on the point where bullets hit, also known as ‘sight in a rifle’. A rifle is considered to be zeroed in when the bullets hit the intended target (point of aim) with a margin of error that is no more than a few inches.

Why Should You Zero Your Rifle at 100?

There is no set rule that you must zero your rifle at 100 yards. If you want, you can zero your rifle for a distance of 50 yards or 150 yards. However, the distance of 100 yards has become a standard for zeroing your scope for a number of reasons and most shooters and hunters do a 100 yard zero.

First, scope manufacturers often set the parallax adjustment for a distance of 100 yards. Parallax is the slight movement you can see on the scope if you move your eye to the left or right while looking through the scope. It makes the target appear slightly left or right from the crosshair. Some scopes allow parallax adjustment for different ranges but many come with parallax set at 100 yards which makes it easier to zero your rifle for the same distance.

Second, it is easy to zero a scope for 100 yards and even beginners can set their scopes for that distance without too much difficulty.

Another reason why 100 yards is preferred is that the distance is far enough to identify if the gun’s scope is lined up with the bore. When you set your zero at 100 yards, make sure to check if the bore and the scope are aligned or not. If they appear to be significantly off, go see a gunsmith.

But this is not to say that your scope must always be zeroed at 100 yards. You can zero your rifle for a longer distance as well. Suppose you go deer hunting where you will probably be shooting from a distance of 200 to 250 yards. If your scope is zeroed at 200, the bullet will only drop a few inches compared to how much it would drop if your scope is zeroed at 100 yards.

The key here is to start with 100 yards, but gradually increase your zero when you get better and need to shoot farther.

Most hunting in the woods or brush will not go over 200 or 250 yards. It’ll be pretty easy to have a 100 yard zero and then align your elevation for a 200 yard shot. If your typical range will be 200 to 300 yards then go and zero at 200 yards. That’ll cover you for most ranges from 100 to 300 yards.

The most important factor is that you write down your ammo, range, wind, etc. so you can repeat those shots exactly when needed. If you zero for your specific ammo but then switch to shoot with a magnum cartridge then your whole setup is off. The speed with which your bullet exits the muzzle is higher and the trajectory of the bullet is completely different.

Your once aligned scope and rifle will be completely out of alignment if you change any of the parameters. You can compensate with bullet-trajectory charts and tables or ballistic programs. But you can’t just assume that your setup and point of aim won’t need any adjusting.

Why Is Zeroing Important?

Zeroing your rifle scope can make a world of difference for your hunting trips. It helps improve accuracy for long-range shooting and allows you to hit within inches of your target.

You see, when you shoot a bullet from your rifle, it does not travel in a straight line. Gravity starts pulling it down the moment it leaves your gun’s barrel. Since the bullet is traveling very fast, gravity does not affect it very much.

However, as the bullet begins to slow down, due to air resistance, the drop becomes quicker. Consider the image below.

Our list and recommendation for the best 200 yard scope

Zeroing a Rifle Scope

In order to make up for the bullet drop, you need to zero the scope so that it shows where the bullet will actually travel at a given distance instead of where the barrel points.

A rifle scope that is zeroed for 100 yards may not be accurate when shooting at a distance of 300 yards. This is because the bullet drop will be higher at a greater distance and you will need to compensate by adjusting the aim. This is why gunners maintain a logbook to keep a record of zero adjustments at different shooting distances.

Bullet Drop Graph for 308

What Do You Need To Zero A Scope?

You need to have the following equipment to zero your rifle accurately.

  1. Your rifle scope is the most important piece of equipment for setting up your zero. Make sure that the scope is installed correctly on the gun. The rings and bolts must secure the mount to the base firmly.
  2. The quality of ammunition also affects your aim when you zero your scope for a specific distance. Bullets have different rates of drop that are affected by the length, weight, velocity, and type of projectile. Hunters should stick to a single type of bullet as they will often need to shoot at different distances.
  3. Bore sights come in two varieties, laser and magnetic. A boresight will save you a lot of ammunition and shoulder wear.
  4. A rifle rest helps keep your gun completely stable while setting up the zero. It helps eliminate chances of human error so it is highly advised to use it when setting up your zero.
  5. A diary and pen are used by many shooters to make calculations while setting up the zero.

5 Steps to Zero a Rifle Scope at 100 Yards

In order to set up your rifle scope at 100 yards, you can follow a 5-step process.

  1. The first thing you can do is to set your rifle, scope and target up. Ensure that the scope is fitted correctly on the rifle. If you are using a rest, secure the rifle on it so that it does not move while shooting.
  2. Once you have the target set up, look through the scope. You must get a clear, distinct image when setting up the shot so make sure magnification is set at the correct range. Fine-tune the scope direction with windage and elevation adjustments to point the reticle at the center of the target.
  3. Once your crosshair is level with the target’s bull’s eye, fire one round and examine where it hits. The point of impact will be the starting position from where you will need to adjust your scope. Some gunners shoot three bullets from the initial position to assess if there is any movement with each shot.
  4. If your shots don’t even hit the target, it could mean your scope requires greater adjustment. You may need to unmount and refit your scope, tightening it in the right direction. If the bullets hit the target with a difference of 1 – 10 inches, you can make adjustments to the scope. You can calculate the level of adjustment required to a scope precisely by counting the clicks needed to adjust the scope in each direction. For example, suppose your scope makes adjustments of ½ inches for each click. If the shot falls 2.5 inches below the target and 3 inches to the left, you will need to adjust aim by 5 MOA up and 6 MOA to the right.
  5. After you have adjusted the scope, try another test shot and see where it goes. If you have made the right adjustments after the initial shot, the rifle’s accuracy should improve and you will be closer to the target. If you are still off by a few inches, make finer adjustments and you should be good to go.

Can You Zero A Scope Without Firing?

You can zero a scope without shooting with the help of a boresight. The boresight helps you determine where the projectiles would go, based on the direction and angle of the gun’s bore. There are three ways you can use bore sights to determine the angle.

First, you can use a visual bore sight by positioning the middle of your rifle’s barrel with the sights. This method can take more time to shoot and doesn’t necessarily work well once you go over a certain distance.

Second, you can use a laser bore sight. This method is quick and easy. The laser is fitted inside your rifle’s muzzle and travels in a straight line. Again, make sure that you adjust the scope for appropriate bullet drop before shooting to improve accuracy.

The third type of boresight is the magnetic kind. It isn’t very popular but still offers an effective way to zero a scope without shooting. Just attach it to the end of the barrel and look through the scope to adjust its crosshair to the grid.

Can You Sight In At 25 Yards for 100 Yard Zero

You can set your scope for 100 yards shooting at a 25-yard distance. You can do this by setting your point of impact lower than your aim at 25 yards. Usually, it requires a lower adjustment of .5″ – 1.5″.

That means if your bullets are hitting the bulls-eye exactly .5 to 1.5 inches below that target at 25 yards, the same scope zero should work accurately at 100 yards.

When Should you Zero at Long-Ranges?

A long-range zero, like a 1000 yard zero only makes sense when you’re shooting that distance. Your bullet will be way off when you zero to 1,000 yards but then try to shoot a range of 100 or 200 yards.

Another limitation you have to consider for long-range is the adjustment range for elevation that your scope provides. If you zero at that distance and then want to shoot at 100 yards you have to adjust your elevation or you’ll be way too high at 100 yards. However, your scope’s elevation range might not be sufficient to adjust by that much and therefore you have a good chance of missing the shot.

The same is certainly true the other way around. If your zero is set at 200 yards or 300 yards and you want to shoot 1,000 yards then you will end up not being able to adjust your elevation enough to compensate for the bullet trajectory. If your point of aim is out 1,000 yards then the drop can be several feet and most scopes won’t have a range amounting to that.

Make sure that you will shoot at around the range that you zero for. If you all the time shoot between 800 and 1,000 yards then zero for that range. Possibly the easiest will be to zero for 900 yards and then have enough elevation adjustment range to compensate for the 100 yards of range.


In this post, we reviewed why it is important to zero your rifle scope and the process for setting up the zero. Hopefully, it helps you with zeroing your scope and picking the right distance to do so.

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Aaron Bennett