How to zero in a thermal scope


A thermal scope is a firearm attachment and sighting device that combines an aiming reticle with a thermographic camera. It serves to provide a clearer image of a living target by measuring the heat put out by the target in contrast with its surroundings. Its use spans from the military to hunters and everything between.

Professional and casual hunters alike may choose to equip a thermal scope to their hunting rifle in order to up their game. The benefits range from being able to more efficiently gauge targets in cloudy or other low-visibility settings to being able to maintain strong sight lines during the nighttime. Thermal scopes are even more advantageous in snowy or other extremely cold environments, as the color contrast between a target and their background will be sharp, clear, and hard to miss.

However, one major prerequisite for being able to adequately set up any thermal hunting excursion is the ability to properly zero in your thermal scope.

zero thermal scope

Zeroing in, also known as sighting, is the process of aligning the sights on a scope to those on the rifle to which it’s attached. It guarantees accuracy and ensures a hunter wastes no shots because of technical inaccuracies.

While zeroing in thermal scopes can take a bit of time getting used to, as with many other more advanced scopes, with practice it can become an efficient way of preparing for a solid hunt.

Step 1: Hit the books

We know, we know. This seems both self-evident and boring, because it involves being at home as opposed to out on the prowl. But while some choose to work hard, we believe in working smart first. And the smartest way to begin any attempt at sighting a thermal scope is by consulting the professionals – by which, we mean the people who built the scope.

If your scope was purchased new, it likely came packaged with a user manual. Consulting this resource is an invaluable time-saver, as not only will the manufacturer fill you in on all the perks and benefits to your new scope, but they’ll also let you know of any quick, surefire ways of getting your scope zeroed in and set up perfectly.

In case your particular scope’s manufacturer manual disappoints, head to the web! Chances are, the manufacturer’s website is complete with any information you could possibly need in order to accurately sight your scope. Certain manufacturers may even have videos dedicated to showing you the do-it-yourself version of scope sighting, to ensure you can get it going and get out there.

Step 2: Hit the crafts store

If the home resources aren’t doing you justice, it may be time to take matters into your own hands. Any sort of targets can work for zeroing in a thermal scope, though one with a heat distinction is naturally best, since the contrast in color will give you the least amount of headache.

For sample purposes, consider using aluminum duct tape over a standard cross target, as it provides an exact center. Exact centers are easier to measure on a grid system, so you have a clearer idea on exactly how much to adjust your reticle after each shot (so maybe keep the smiley face target for another night).

Step 3: Shooting time

Yes, it’s finally here. Once your rifle is all set up and ready to go, get your target prepared. At first, scope as best as you can, and once you have your shot ready, let loose. As with other pre-scoped shots, your accuracy will be likely abysmal, but this is exactly the point. Ensure you pick up the exact spot you hit (generally this will be a white dot on the target, due to the heat of the recently-fired bullet).

Step 4: Get out the protractor

If you don’t have a grid already set up on your target for easy reference, use a ruler or other measuring tool to get a good idea of your accuracy range. For many people, the first few shoots tend to skew left and down of center, but this really varies between guns, scopes, and hunters.

Step 5: Adjust the reticle

The reticle, or mid-scope dot that you are using to aim your rifle, can be adjusted in different ways, depending on the model and manufacturer of your gun. While older models may adjust the reticle’s position manually using a knob or gear system, newer models may include automatic adjustment with the screen reacting to preset images or markers. For these scopes, sighting may only take one or two trials. However, for older or more traditional models, you will likely be needing to adjust more than once, as you get closer and closer to your target, which leads to step 6…

Step 6: Rinse & repeat

Patience is key here! Continually repeat this process, moving along the x– and y-axes until you arrive to your perfect spot at zero degrees on both axes. It can be tiring, so having a partner stand at a safe distance and do your calibration calculations for you can be a big help. Eventually, however, you will reach the point (0,0) where you are completely zeroed in (it’s okay if, due to scope/weapon imperfections, you are within a fraction of a centimeter in any direction; we promise, none of your targets will complain).

Step 7: Happy hunting!

At this point, you should be able to fire numerous times and hit the same point on the target with more or less perfect precision. This will mean your scope’s sights are lined up just right with your rifle’s, and you are ready to go out and get hunting. Enjoy your thermal scope, and try it out in different environments and conditions, at various distances, and on different targets. And if you find yourself enjoying the thermal scope but wanting to change your game up a bit, consider switching to a night vision scope. It has its own entire process for zeroing, but just like the thermal, is a solid way of diversifying your hunting.