How to Zero a Thermal Rifle Scope: Step-by-Step Guide

Getting your hands on the best thermal rifle scope is only half the battle. The other half is zeroing it correctly so that where you aim is exactly where your bullet lands. For first-time thermal scope users, this process can feel unfamiliar, especially when you are used to daylight optics with visible crosshairs and paper targets you can see with the naked eye.

This guide walks you through the entire zeroing process from start to finish. We will cover how to zero thermal scope systems using both traditional range methods and the smart built-in tools found on modern optics like the ATN ThOR 6 and ATN ThOR 6 Mini. Whether you are a hog hunter dialing in before a night hunt or a first-time thermal buyer figuring out where to start, this is the only zeroing guide you need.

Why Zeroing a Thermal Scope Is Different From a Traditional Scope

With a traditional daytime scope, you can see your target, your bullet hole, and your reticle all at the same time. You make adjustments, shoot again, and confirm. Simple enough.

With a thermal scope, the process is fundamentally different. You are working with heat signatures instead of visible images. Standard paper targets with black bullseyes do not stand out in thermal. Your bullet holes do not show up the same way they would under magnification in daylight. And if you are rushing, you might lose the point of impact image before you have a chance to make your adjustments.

That is why the best modern thermal scopes have built-in features specifically designed to make thermal scope sighting faster, easier, and more precise. Features like Zeroing Freeze, heated targets included in the box, and digital reticle adjustment systems solve the problems that used to make thermal zeroing frustrating for new users.

Once you understand the workflow, zeroing a thermal scope is actually faster than zeroing a traditional optic. You just need to know the right steps.

What You Need Before You Start

Before heading to the range, make sure you have everything in order. Missing one item can turn a 30-minute zeroing session into a wasted afternoon.

• Your thermal rifle scope properly mounted on your firearm with rings or a Picatinny rail
• A stable shooting rest or bench rest setup
• The heated target included with your ATN ThOR 6 or ThOR 6 Mini, or an alternative heat-producing target
• Ammunition consistent with what you plan to hunt with
• A fully charged battery or fresh batteries
• Your scope's user manual for reference on menu navigation
• Eye and hearing protection

One note on targets: standard paper targets are not ideal for thermal zeroing because they tend to blend into the background thermally. ATN includes a heated target with both the ThOR 6 and ThOR 6 Mini specifically for this reason. That target produces a heat signature your scope can clearly detect, giving you a defined aiming point in the thermal image. Use it.

Step 1: Mount Your Scope Correctly

Proper mounting is the foundation of any successful zero. If your scope is not mounted solidly and level, no amount of reticle adjustment will produce consistent accuracy.

The ATN ThOR 6 uses 30mm rings, which are not included, so make sure you have the right hardware before you start. The ATN ThOR 6 Mini mounts directly to a Picatinny rail, making installation more straightforward.

When mounting, torque your rings or mount to the manufacturer's specifications. Do not over-tighten. Make sure the scope is level both side to side and along the bore axis. A tilted scope will cause your shots to drift as you increase range, which will make zeroing at distance impossible to get right.

Set your eye relief before locking anything down. For both the ThOR 6 and ThOR 6 Mini, the eye relief is 50mm. Position the scope so you have a full, clear image when you bring the rifle to your shoulder naturally.

Once the scope is mounted and torqued, power it on and spend a few minutes getting familiar with the display and menu system before you shoot anything.

Step 2: Set Up Your Diopter and Focus

Before you fire a single round, you need to make sure the image you are seeing is as sharp as possible. A blurry display will make it impossible to see exactly where your reticle is sitting relative to your target.

Both the ThOR 6 and ThOR 6 Mini feature a diopter adjustment with a range of -5 to +5D. Adjust the diopter until the reticle appears sharp and crisp to your eye. This is an eyepiece adjustment, not a target focus adjustment, and it needs to match your vision.

Next, focus the objective lens on your target. The ThOR 6 uses a central knob control for manual focus. The ThOR 6 Mini uses a front lens adjustment. Turn the focus control until your target appears as sharp as possible in the thermal image. At your zeroing distance, the heated target should appear well-defined with clean edges.

If your image looks soft or smeared even after focus adjustment, run a Non-Uniformity Correction (NUC). Both the ThOR 6 and ThOR 6 Mini support Auto, Semi-Auto, and Manual NUC. Running a NUC clears sensor drift and restores image uniformity. Cover the lens, trigger the NUC from the menu, then uncover and re-check your image.

Step 3: Perform a Thermal Bore Sight

Before you shoot, performing a thermal bore sight gets your reticle close enough to the target that your first shot will land on paper, or at least in the right area. This saves ammunition and time.

Here is how to do it with a thermal scope:

• Place your heated target at 25 yards to start. This is a short enough distance that even if your scope is off by a significant amount, you will still hit the target area.
• Remove the bolt from your rifle if it is a bolt-action, or use a thermal-compatible bore sighter if you prefer a tool-based approach.
• Look through the bore and center your heated target in the bore axis as best as you can.
• Without moving the rifle, look through the scope and note where your reticle is sitting relative to where the bore is pointing.
• Use the scope's digital reticle adjustment to move the reticle toward the bore's point of aim.

The digital nature of thermal scope reticles makes thermal bore sight adjustments faster than turning turrets on a traditional scope. On the ATN ThOR 6 and ThOR 6 Mini, reticle adjustments are made through the menu system rather than physical turrets. Navigate to the zeroing menu and use the directional controls to move your reticle.

After your bore sight adjustment, you are ready to fire your first rounds.

Step 4: Fire Your First Group at 25 Yards

Start at 25 yards. This is the standard first zeroing distance for any rifle optic, thermal or traditional. It gets your reticle onto the target quickly without burning through a box of ammunition chasing cold shots at 100 yards.

Use a solid bench rest. Shooting from a bench eliminates as much human error as possible and lets you see exactly what the scope and rifle are doing rather than what your hold is doing. Use a rear bag if you have one.

Fire a three-shot group. Let the barrel cool slightly between shots if you are shooting a bolt-action, but do not let the heated target cool significantly. You need to see it clearly in the thermal image.

After your three-shot group, check where the shots landed in relation to your reticle's point of aim. With a thermal scope, bullet holes in a heated target may appear as slight temperature disturbances. If the target is close enough and warm enough, they will be visible. You can also walk downrange between strings to physically inspect the target.

Step 5: Use Zeroing Freeze to Lock In Your Adjustments

This is where the ATN ThOR 6 and ThOR 6 Mini separate themselves from entry-level thermal optics. Both scopes feature a thermal scope first zero tool called Zeroing Freeze that fundamentally changes how you make adjustments.

Here is how Zeroing Freeze works and why it matters for how to zero thermal scopes effectively:

Immediately after a shot, the point of impact retains heat for a brief window. Zeroing Freeze lets you pause the live image at the moment of impact so you can see exactly where the bullet struck in relation to your reticle. The image stays frozen on your display while you navigate the zeroing menu and move the reticle to the point of impact without any time pressure.

This eliminates one of the biggest frustrations of thermal zeroing: the shot disappearing from the image before you can make your adjustment. With Zeroing Freeze, you have as much time as you need. Move the reticle to the bullet's point of impact, confirm the placement, and save the zero.

The workflow looks like this:

• Fire a shot at your heated target
• Activate Zeroing Freeze immediately after the shot
• Note where the bullet impacted relative to your reticle
• Use the directional controls in the zeroing menu to move the reticle to the point of impact
• Unfreeze the image and confirm your adjustment
• Fire a follow-up shot to verify

Repeat this process until your reticle is centered on your shot group at 25 yards. Then move to your final zeroing distance.

Step 6: Move to Your Final Zeroing Distance

Once you are hitting your point of aim at 25 yards, it is time to move to your intended zeroing distance. For most hunters using a thermal rifle scope, this is typically 100 yards. Hog hunters who shoot at closer ranges sometimes zero at 50 yards. Predator hunters or those making longer shots might zero at 100 to 200 yards depending on their terrain and typical engagement distances.

At your final zeroing distance, set up a fresh heated target and repeat the process:

• Fire a three-shot group from a supported position
• Activate Zeroing Freeze after a representative shot
• Adjust the reticle to center on your group
• Fire a confirmation group to verify

You want your group to be tight before you commit to a final adjustment. A spread-out group means the rifle, ammunition, or your hold is introducing variables. A tight, consistent group means any remaining error is purely in the reticle's point of aim versus point of impact, and that is easy to correct.

Once you are satisfied with your zero at distance, save the profile.

Step 7: Save Your Zero as a Weapon Profile

Both the ATN ThOR 6 and ATN ThOR 6 Mini support multiple saved weapon profiles. The ThOR 6 LRF models and the ThOR 6 Mini both let you store up to five custom profiles. This is a feature that serious hunters will use constantly.

After confirming your zero, save it as a named profile in the scope's menu. Label it clearly so you can identify it later, for example by caliber or rifle name. If you run this scope on multiple rifles or switch calibers between seasons, having individual saved profiles means you never have to re-zero from scratch. Just select the correct profile for your current setup and you are ready to go.

For the LRF models of the ThOR 6, you can also pair your saved zero with the built-in ballistic calculator. Once the ballistic calculator has your rifle's data and your zero distance, it automatically adjusts the point of aim for range and angle when you use the integrated laser rangefinder. This is especially valuable for shots beyond 150 yards where bullet drop becomes a meaningful factor.

Step 8: Confirm Your Zero in Low Light or Darkness

This step is optional but strongly recommended, especially if you plan to hunt at night. Your thermal scope performs the same in darkness as it does in daylight, but your ability to read the display, navigate the menus, and control your rifle may vary when you are outside in the dark for the first time.

Take your rifle out at dusk or full dark with your heated target at your zeroing distance. Fire a confirmation group. The thermal image should be just as clear as it was during your daylight zeroing session. The heated target will actually stand out more crisply in a cool nighttime environment.

Pay attention to the color palette you have selected. Both the ThOR 6 and ThOR 6 Mini offer six color palettes: White Hot, Black Hot, Iron Red, Alarm, Green Hot, and Sepia. Different palettes work better in different environments. White Hot is one of the most commonly used for hunting because hot targets appear bright and distinct against a darker background. Try a few palettes and note which one gives you the clearest reticle-to-target relationship for your specific hunting environment.

ATN ThOR 6: The Full-Size Thermal Scope Built for Serious Hunters

If you are looking for the best thermal rifle scope with maximum detection range, the ATN ThOR 6 is where you want to focus your attention in 2026. This is a full-size thermal riflescope powered by ATN's 6th Generation thermal engine, and it is built for hunters and professionals who demand everything from their optic.

Sensor Performance and Detection Range

The ThOR 6 is available in 384x288 and 640x512 sensor resolutions, both built on a 12-micron pixel pitch. The thermal sensitivity rating is 15mK NETD or better, which means this sensor can detect temperature differences as small as fifteen thousandths of a degree Celsius. In practical hunting terms, that translates to detecting heat signatures through dense brush, fog, or in high-heat ambient environments where lower-sensitivity sensors struggle to separate target from background.

Detection range varies by model. The ThOR 6 325 with a 384x288 sensor and 25mm lens reaches 2,300 meters of detection range. Step up to the 640x512 sensor with a 50mm lens on the ThOR 6 650 model and detection range reaches 3,650 meters. For most hunting applications, even the entry-level ThOR 6 provides far more detection range than the shooter's practical engagement range.

SharpIR AI Image Enhancement

What makes the ThOR 6 stand apart from raw sensor specs is ATN's proprietary SharpIR AI image enhancement. This system processes every pixel in real time, sharpening edge definition and improving contrast between target and background. The result is that a deer or hog standing in brush does not just appear as a vague heat blob. It appears as a defined shape with clear edges, which makes target identification and shot placement significantly more confident.

SharpIR operates automatically without any input from the shooter. There is nothing to toggle on or configure. It is always working, always optimizing the image you see through the eyepiece.

Display Quality

The ThOR 6 features a 0.49-inch OLED display at 1920x1080 resolution. OLED technology produces true blacks and high contrast, which matters significantly in a thermal scope because the contrast between cool backgrounds and warm targets is where your brain processes the image. A high-quality OLED display makes that contrast crisper and reduces the eye fatigue that comes with long scanning sessions.

Recording and Connectivity

The ThOR 6 includes onboard video and audio recording with 64GB of internal storage, so there are no SD cards to manage. Recoil Activated Video automatically captures footage starting 10 seconds before your shot and continuing 10 seconds after, triggered by the recoil itself. You do not have to do anything to capture your shot on video.

Built-in Wi-Fi connects to the ATN Connect 6 app on iOS and Android, turning your phone or tablet into a live viewfinder. This is useful both for guiding new hunters and for reviewing footage in the field without going back to camp.

Hot Point Tracking and Picture-in-Picture

Hot Point Tracking automatically identifies and highlights the hottest object in your field of view. In a dense treeline at night, this means the scope is constantly directing your attention toward heat signatures rather than requiring you to scan the entire image manually. For hog hunting over bait or scanning fields for coyotes, it accelerates target acquisition significantly.

Picture-in-Picture mode lets you zoom in on the target with a magnified inset window while keeping your full field of view active in the main display. This means you get the precision of high magnification without losing situational awareness of what is happening around your target.

ThOR 6 Specifications at a Glance

• Sensor: 12-micron VoX Uncooled Focal Plane Array
• Resolution options: 384x288 or 640x512
• Thermal sensitivity: 15mK NETD or better
• Display: 0.49-inch OLED at 1920x1080
• Magnification: 2-16x to 3.5-28x depending on model
• Digital zoom: 1x, 2x, 4x, 8x
• Battery life: approximately 9 hours with two 18650 batteries
• Internal storage: 64GB
• Weight: 790g to 855g depending on model
• IP rating: IP67 waterproof
• Recoil rating: 6,000 joules
• Eye relief: 50mm
• Detection range: 2,300m to 3,650m depending on model
• Color palettes: White Hot, Black Hot, Iron Red, Alarm, Green Hot, Sepia
• Operating temperature: -30C to +55C

ATN ThOR 6 Mini: The Compact Thermal Scope That Does Not Cut Corners

The ATN ThOR 6 Mini was designed for hunters who want the same 6th Generation thermal performance in a package that weighs under 580 grams in the heaviest configuration and as little as 500 grams in the lightest. If you are running an AR pistol, a lightweight bolt gun, or you simply spend a lot of time on your feet during a hunt, the ThOR 6 Mini makes a compelling case as the best thermal rifle scope for mobile hunters.

Sensor Options and Detection Range

The ThOR 6 Mini offers six model configurations covering three sensor resolutions: 256x192, 384x288, and 640x512. The 256x192 models feature an enhanced sensitivity sensor with a 20mK NETD rating and are available in 15mm and 25mm lens configurations. The 384x288 and 640x512 models step up to an 18mK NETD high-sensitivity sensor.

Detection range scales with sensor and lens choice. The ThOR 6 Mini 215 with a 256x192 sensor and 15mm lens delivers 1,200 meters of detection. The ThOR 6 Mini 650 with a 640x512 sensor and 50mm lens reaches 3,500 meters. For most night hunting applications including hogs, coyotes, and feral predators, any model in the ThOR 6 Mini lineup provides ample detection range well beyond realistic shooting distances.

Same Core Features in a Smaller Package

Despite its compact dimensions, the ThOR 6 Mini does not remove the features that make zeroing and hunting effective. It includes Zeroing Freeze for precise reticle adjustment, Hot Point Tracking for fast target identification, Picture-in-Picture for zoomed accuracy with maintained situational awareness, and Reticle Transparency Control for an unobstructed sight picture.

SharpIR AI image enhancement is present on all ThOR 6 Mini models, running the same real-time pixel optimization that defines the 6th Generation platform. The 384x288 and 640x512 models use the same 0.49-inch 1920x1080 OLED display as the full-size ThOR 6. The 256x192 models use a 0.32-inch 800x600 OLED display appropriate for their sensor resolution.

Multiple Weapon Profiles

Like the full-size ThOR 6, the ThOR 6 Mini supports up to five saved weapon profiles. If you run the same optic on a suppressed .223 and a .300 Blackout, or you want to move it between rifles during different seasons, saving individual profiles per setup means you are never starting from zero again. Select the profile, confirm your zero with a single shot if conditions have changed significantly, and hunt.

Battery Life and Power System

The ThOR 6 Mini is powered by a single 18650 rechargeable battery. The 256x192 models deliver approximately 8 hours of runtime. The 384x288 and 640x512 models deliver approximately 7 hours. For all-night hog sessions or extended predator hunts, carrying a spare battery and swapping mid-hunt takes seconds. The replaceable design means you are never stuck waiting for a charge.

ThOR 6 Mini Specifications at a Glance

• Sensor: 12-micron VoX Uncooled Focal Plane Array
• Resolution options: 256x192, 384x288, or 640x512
• Thermal sensitivity: 20mK NETD (256x192 models), 18mK NETD (384x288 and 640x512 models)
• Display: 0.32-inch OLED at 800x600 (256x192 models) or 0.49-inch OLED at 1920x1080 (384x288 and 640x512 models)
• Magnification: 2-16x to 3.5-28x depending on model
• Digital zoom: 1x, 2x, 4x, 8x
• Battery life: approximately 7 to 8 hours with one 18650 battery
• Internal storage: 64GB
• Weight: 500g to 580g depending on model
• IP rating: IP67 waterproof
• Recoil rating: 6,000 joules
• Eye relief: 50mm
• Detection range: 1,200m to 3,500m depending on model
• Color palettes: White Hot, Black Hot, Iron Red, Alarm, Green Hot, Sepia
• Operating temperature: -30C to +55C
• Mounting: Picatinny rail

ThOR 6 vs ThOR 6 Mini: Which One Should You Zero and Hunt With?

The answer comes down to your hunting style, your rifle setup, and how far you realistically shoot.

If you hunt from a fixed position, a blind, or a truck, or if you frequently shoot at longer ranges where maximum detection distance and the highest available magnification matter, the full-size ATN ThOR 6 is the better choice. Its nine-hour battery life, larger lens options, LRF models with integrated ballistic calculators, and slightly longer detection ranges on equivalent sensor configurations give it an edge for those applications.

If you move through terrain, hunt on foot, or want to keep total rifle weight down without sacrificing thermal performance, the ATN ThOR 6 Mini is the smarter pick. At under 600 grams even in the top-tier configuration, it is meaningfully lighter than the full-size ThOR 6, and it shares the same 6th Generation thermal platform. The SharpIR AI enhancement, Hot Point Tracking, Zeroing Freeze, and multiple weapon profiles are all present. You are not trading capability for size in any meaningful way for hunting distances under 500 yards.

Common Zeroing Mistakes and How to Avoid Them

Even with the right scope and the right tools, first-time thermal users make predictable mistakes during zeroing. Here is what to watch for.

Trying to Zero at 100 Yards Before Establishing a 25-Yard Zero

Skipping the 25-yard step wastes ammunition. If your scope is significantly off-axis from your bore, you may not even hit your target at 100 yards, let alone establish a useful group to measure. Always start at 25 yards, get on target, then move out.

Not Running a NUC Before Zeroing

A Non-Uniformity Correction takes seconds and can meaningfully improve image quality. If you skip it, you may be zeroing based on a slightly degraded image that introduces false impressions of where your reticle is sitting. Run a NUC at the start of each session.

Using a Target That Does Not Show Up in Thermal

Standard paper targets are invisible in thermal. Use the heated target that ATN includes with both the ThOR 6 and ThOR 6 Mini. If you need an alternative, a water bottle filled with warm water, a chemical hand warmer attached to a backing, or any object warmer than the ambient background will work. The target needs to produce a heat signature for the scope to detect it clearly.

Making Adjustments Without Using Zeroing Freeze

Trying to remember where a shot landed and then manually adjust from memory leads to overcorrection and wasted rounds. Use Zeroing Freeze. It is there specifically to solve this problem, and it works exactly as described. Freeze the image, take your time making the adjustment, unfreeze, and confirm.

Not Saving the Profile After Zeroing

If you zero correctly and then do not save the profile, you may lose your zero if the scope resets or if you navigate away from the zeroing menu without confirming the save. Always navigate to the profile save function and confirm before powering down.

Zeroing in a Warm Environment Without Accounting for Heat Mirage

Zeroing in hot midday conditions over warm pavement or a sun-baked field can introduce heat distortion that slightly shifts the apparent position of targets at distance. When possible, zero in conditions similar to when you plan to hunt. For most thermal hunters, that means cooler temperatures in the early morning or evening, which produces the clearest thermal contrast and the most accurate zero confirmation.

After the Zero: Using Your Thermal Scope in the Field

Once your zero is confirmed and saved, you are ready to hunt. But a few final considerations will help you get the most out of your thermal scope from the first night out.

Use Hot Point Tracking during initial scanning to let the scope direct your attention to heat sources in the field of view. Once you identify a target, switch to Picture-in-Picture if you want to zoom in without losing your peripheral awareness.

Adjust your color palette based on environmental conditions. In cold weather, White Hot creates very high contrast and is easy to read. In warm conditions where ambient temperature is closer to game body temperature, Black Hot or Iron Red can help separate targets from background more clearly.

Keep Reticle Transparency adjusted to where the reticle is clearly visible against your target without obscuring the point of aim. In high-contrast situations where a target appears very bright, a slightly reduced reticle brightness helps you see the exact center of your crosshair.

Verify your zero at the start of any new hunt if the rifle has been transported or if significant time has passed since your last shooting session. Thermal scopes are digital and do not walk their zero the way traditional scopes sometimes do, but rifles move in safes, vehicles, and cases. A single confirmation shot takes 30 seconds and tells you everything you need to know.

Final Thoughts

Zeroing a zero thermal scope system correctly is the difference between a rifle that performs and one that frustrates. The process is straightforward when you follow it in order: mount solidly, set focus and diopter, bore sight, shoot at 25 yards, use Zeroing Freeze to make precise adjustments, confirm at your final zeroing distance, and save your profile.

The ATN ThOR 6 and ATN ThOR 6 Mini make this process as streamlined as any thermal scope available in 2026. With Zeroing Freeze eliminating the time-pressure problem, heated targets included in the box, and multiple saved weapon profiles for versatile use across different rifles, the zeroing experience on these scopes is