How to Sight in a Thermal Scope 

 August 5, 2019

By  Randy Angwin

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Last updated on July 11, 2021

One of the advantages of a thermal scope is that it gives you vision through dense fog and even thick bushes. But in order to see with absolute clarity with your new thermal scope, you need to know how to sight the device. 

Sighting a scope is the process of properly aligning the device with the barrel of your weapon. The process also allows you to hit your target accurately. If you don’t properly sight your scope you will not be able to hit your targets.

So how do you sight your own thermal scope and how does it differ from day time scopes? Let’s find out. 

Thermal Sighting vs Day Time Sighting

Day Time Sighting

Sighting a day scope is slightly different from how you would adjust your thermal optic. This is because you have to ensure you have a stationary target that is either warmer or colder than your surroundings so you can see exactly where your shots are hitting and make adjustments as necessary.

With daytime optics, you’ll often find that you have to use buttons to move the reticle. Thermal reticles differ according to the brand you’re using. To understand how to adjust your thermal scope study your user manual as each thermal scope differs in it's adjustments.

Take time to learn your thermal optic and experiment with it using the menu system before you go hunting or go to the shooting range.

What Targets to Use

There are two ways you can make your own target but you may have to source a few supplies from your local store.

Both methods require a heating pad or object that will be warmer or cooler than your surroundings. A target with heat distinction will allow you to zero your scope more effectively. The temperature contrast of the heating pad or other object such as a heated water bottle or reflective tape will provide a clear view of your target.

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  1. For the first method consider using tape to create a cross target. The cross target gives you a center point that’s easier to measure if you’re working on a grid system. The cross target will give you an idea of how much to adjust your reticle after the shots you take. Reflective tape works well for this as you can easily make a cross.
  2. Another method you could try is using a honeycomb sign you can find at a home improvement store. You’ll need your hot or cold object so you can attach it to the center of the honeycomb sign. You can fold the heating pad in half for a more precise zero or again use reflective tape.

If you don’t have the time to make your own target you can purchase a heated target from a company called Thermbright. These targets glow under thermal optics and make sighting in your thermal scope very easy.

Recommended Distance for Target

When you’re adjusting your optic it’s important that you use the same rounds you would when hunting or target shooting. Bullet drop varies according to the following:

  • Velocity
  • Bullet weight
  • The caliber you’re using

You need to zero your thermal scope for the ranges you’ll be using the most. The recommended distances to adjust your optic are between 50 to 200 yards. But it’s best to practice at different distances because sometimes at a closer range you can hit an inch above the reticle. 

When you’re hitting an inch above the bulls-eye at a far distance such as 200 yards you’re almost certain to miss your target once you’re in the field. So be sure to sight your thermal scope in at various distances unless you know you will always be shooting targets from a specific distance.

Have a Practice Round

After your target is in place and your weapon is loaded & you’ve worked on your optic it’s time to have a practice round.

  • You need to be in a stable shooting position and your rifle needs to be steady so you can maximize your zero.
  • Start the zero process by firing three rounds into your target.
  • Observe where the rounds hit the target and do an approximation on your vertical & horizontal distances to the middle of your cross target.
  • Write these measurements down. This will give you the information you need to make the necessary adjustments to your thermal optic. 

You only need to zero your optic when you’re shooting off target. Once you’re hitting on the target you don’t need to zero your weapon further. 

How to Make Adjustments

Depending on the product you’re using there should be an adjustment mechanism on your thermal optic. Use this to make any adjustments to your optic after firing at your target. 

The horizontal and vertical distances you’ve written down will help you make your adjustments. If you’re one or two inches off your target you can dial in to set your scope. To do this correctly always keep your firing patterns, positions and distances consistent.

Keep firing your rounds and keep making adjustments to your thermal optic until you get an accurate shot on your bullseye.

As mentioned before, each brand may have its own procedure so refer to your manual on how to make adjustments to your thermal scope.

What is a One Shot Zero?

A one shot zero is firing one round instead of three to zero your thermal optic. People prefer to do this so as not to waste ammo. To perform a one shot zero your rifle needs to be extremely stable at all times and you need a boresight.

A boresight is simply another method of adjustment to your optic to align your sight with your barrel. This is used to pre-align the sight which makes zeroing quicker. 

Many of the top-rated thermal scopes allow you to take one shot aimed directly at the bulls-eye. You can then "freeze" the retical and move the cross-hairs to where your shot landed once you have done this you can save the settings and your next shot should be directly on the bulls-eye.

This helps save ammo and time on the range sighting in your thermal scope.

What is Pulsar’s “One Shot Zero with Freeze” function?

Sometimes keeping your POI (panoramic optical imager) steady is difficult. That’s why Pulsar has designed a technology to keep your POI steady. Now you can perform a precise shot every time. 

To use this function double your base magnification. This reveals the point of impact of your previous shot. You can freeze the image you see so you can position the secondary adjustment which shows an X over the first POI. Save this data and take your second shot. This should be dead center on your target. 

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Final Thoughts:

Now that you know more about how to use your thermal scope, it’s time to put your skills to the test. Set up different types of targets to see if you can use your scope to hit your target accurately. 

Experiment with your sighting and zeroing methods at different distances. Try using as few rounds as possible when zeroing your thermal optic. If you can get an accurate shot dead center on your target you’ve succeeded in sighting your scope correctly. Now you’re ready for action in the field. 

About the author 

Randy Angwin

Randy Angwin holds a master of science degree from University of Florida. He is an expert in infrared and night vision technology. His knowledge helps us staying on top of the latest trends in the thermal industry. When not working, Randy likes to hunt and spend time with his two German shepherds.

  • The problem i have had with most thermal scopes is once you have done the one shot zero set up a lot of the time the reticule is not centre in the screen.
    You can sort this if high or low but not left to right.
    Do you have info on how to sort this problem out.
    Regards kev.

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