Precision shooting scope adjustment

Adjusting a rifle scope is an essential step in the life of a sport shooter or hunter; knowing how to do it yourself is a step in itself in the development of weapons-related skills. However, there are a few tricks that can help take this practice to the next level.

In this article, we will guide you step by step through adjusting your optics.

The few prerequisites: 

We assume that your scope has already been properly mounted: leveling, correct eye relief, etc. This is to condense the size of our text. A scope is said to be adjusted when the bullets hit the point targeted by the reticle. The reticle can be moved by using the turrets to match the pointing of the reticle to the location of the impacts.

Step 1: Borescope your riflescope

Sometimes when mounting the scope, it is not on its optical center, resulting in your first bullet being off target even at short distances, this situation can be particularly dangerous...

This is why we recommend carrying out a so-called “simbleautage” step beforehand for the first shot.

The method for making a simbleautage

You will need to place a large target (C50 for example) at a relatively short distance of 25 meters or 50 meters (100 meters for those who are used to it). You will then need to rest your weapon on a stable support (tripod / bipod / bag / etc.). You can then remove the slide so that you can look through the axis of the barrel and point it towards your target.

Keeping the weapon perfectly still, now look through your scope. The reticle should be centered on your target at the same time as your barrel is pointing at it.

If your gun and scope are not pointing at the target at the same time, you will need to click on the turrets of your scope.

The top turret allows you to raise or lower the reticle. The direction of rotation is generally indicated by the word “U” or “Up” which means to raise in English. In this direction of rotation, the point of impact will rise in the target (so my reticle descends).

The side turret allows the reticle to be moved laterally from left to right or from right to left depending on the direction of rotation of the turrets. As on the elevation turret, an “R” is generally present meaning “Right” in English indicating the direction to send the impact to the right.

When the reticle and the axis of your gun are pointing at the same time at the center of your target, you can reset your slide and fire your first bullet on target!

TIP: Some weapons do not allow the slide to be removed (AR-15, lever-action rifles under guard, etc.). For these weapons, we recommend firing your first bullet at a reduced distance of between 10 and 20 meters to guarantee a bullet on target.

Step 2: Bring the impacts closer to the center

This step involves bringing your impacts closer to the center of the target. There are several possible methods for this.

Method 1: The universal method of converting your scope to clicks

Our first technique is to measure the location of our first impact relative to the target point (center of the target). This is measured as a difference in height and width. Insert IMAGE #3

Once your measurements are taken, you will then need to convert the measurements taken in order to move them from centimeters to units of angles. In fact, all scopes work either in MOA (Minute Of Angle) or in Mil (Milliradian), which are two units of angles (one imperial, which comes to us from across the Atlantic, one metric). Your scope will necessarily have a subdivision of one of these units of angles written on it (⅛ MOA, ¼ MOA, 0.1 mil).

This element allows you to know the value of the correction of each click

You will just have to convert these measurements using the attached conversion table.

Let's take an example: I measure a height difference in target of 14cm (140mm) at a distance of 100 meters If my scope is in ¼ MOA the value of a click at the distance is 7.3mm I just have to divide the difference measured in target (in mm) by the value of a click -> 140/7.3 = 19 clicks, as I cannot make half clicks, I would make 19 clicks.

In our case:

Our target is at 100 meters, our scope is graduated in 0.1 mil at this distance each click is 1cm, we will therefore have to go down 14 clicks and send to the left 7 clicks.

-> Advantage: Low cartridge consumption, does not require a perfectly stable support (vice), allows you to work on some angle conversion calculations, maths never hurts!

-> Disadvantage: You have to go back and forth, have a tape measure and a calculator

Method 2: Using a First Focal Plane Reticle “FFP” for TLD Scopes

This method involves measuring in the reticle of your scope the difference in height and width between the point aimed at and your first impact.

How do you know if your riflescope reticle is at the 1st focal plane?

The reticle “magnifies” with the zoom, your graduations always point to the least points in space whatever the zoom value of your scope, allowing you to measure angles or distance whatever the value of your zoom.

Using your reticle, you measure directly in units of angles, no calculations required!

You will need to point your reticle at your target point and measure the number of graduations vertically and horizontally to find your first impact.

Once the number of graduations is noted, you will need to refer to the reticle instructions to find out the value of a graduation (even if most reticles are graduated in 0.2 mil these days). Of course, once the correction is measured, all you have to do is transfer it to your turrets to make the adjustment, paying attention of course to the direction of rotation of the turrets.

In our example, here we measure 7 graduations vertically, 3.5 graduations horizontally. As the reticle of our scope is graduated in 0.2 mil (value of 2 clicks)

7 graduations = 7x0.2 = 1.4 mil = 14 vertical clicks

3.5 graduations = 3.5x2 = 0.7 mil = 7 clicks to the left.

-> Advantage: No need to move from your seat, allows you to take control of the scope reticle, does not require extremely stable support.

-> Disadvantage: Requires a telescope at the first focal plane…

You can now, whichever method you used, fire your second ball, which should be very close to the center…

Step 3: Finalize with a precise grouping

Now we're going to switch to a smaller target! Because the smaller the target, the better the shooter's aim will be, the center circle of a C50 target is too big to aim with the best possible accuracy.

An improved version can be downloaded here: HERE

We use a rather unusual visual for our zeroing: a crosshair with a circle at the bottom. If your reticle has a center dot, you can center it with the target circle. If your reticle has a solid crosshair, you can overlay it with the crosshair of the reticle.

It is now time to group at least 10 shots in order to center your scope on the center of a large group.

Example of using this target:

We aim at the bottom circle and make this grouping of 19 shots, which arrives higher than our aiming point

To measure the difference in elevation and lateral, using a caliper is the simplest and quickest method.

There are also apps that scan your target to give you the correction of your grouping relative to the aimed point! (Hornady 4DOF for example)

Here the application tells us that our grouping of a respectable size of 2.56 cm is located:

- 1.68 cm above our target point (Elevation Offset)

- 0.11 cm to the right of the target point (Windage offset)

Since our target is 100 meters away and our scope is graduated in 0.1 mil (1 click = 1 cm at 100 meters), all that's left to do is click:

- Move down 2 clicks, our grouping will be 0.32 cm low (1.68cm - 2 cm = - 0.32cm), but we can't do better!

- Regarding left right, No need to click, we are at 0.11 cm (10% of the value of a click)

And here is our perfectly done adjustment!

If you are not confident, you can always regroup to make sure you did not make a mistake (rotation direction or conversion)

Now that you have a reliable aiming point hit point, all that's left is to zero your turrets, this step involves placing the origin of the turrets on our setting, as it's unlikely you'll have landed on the "0" value once set!

How to zero your rifle scope?

The first step is to “disengage” your turret from its axis.

This operation varies depending on the model of your scope, we invite you to refer to the instructions for your optic. In our case, we need to unscrew three small hexagonal screws placed on the periphery of the turret. Some scopes have a central screw to unscrew (be careful to hold the turret firmly when unscrewing to avoid clicking when loosening the turret)

Now that your turret is “free” and when you turn it you no longer hear “clicks”, you just have to align the turret on zero and tighten the clamping screw(s) according to your model.

Of course, this operation must be done for both turrets.

We advise you to group at 100 meters to ensure that no clicks have interfered with your adjustment when disengaging the turret, it happens more often than you think!

And there you have it, you now have a perfectly adjusted and zeroed scope!