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ATN ThOR 4 640 Thermal Rifle Scope

ATN ThOR 4 640 Thermal Rifle Scope Review

The ATN ThOR 4 series is an upgrade from the ATN Thor HD series. The ATN ThOR 4 640 takes all the features of the ATN ThOR-HD 640 and improves on them as well as adding new ones.

The ATN ThOR 4 640 focuses a lot on optical performance and improving shot accuracy with features like a built-in ballistic calculator, a smart rangefinder, and a smart mil-dot reticle.

A new feature in the ThOR 4 series is dual HD video recording and streaming. You can simultaneously record video on an SD card and stream on the ATN Obsidian app.  

The ATN ThOR 4 640 is a great choice for hunters looking for thermal rifle scope with top of the line optical performance and HD video recording and streaming.

Of course, these features don’t come cheap. The ATN ThOR 4 series is fairly pricey. If you are looking for a more budget-friendly alternative, see our reviews of the best cheap thermal scopes.

ATN ThOR 4 640 Key Features

ATN ThOR 4 features

Here are the top 10 features of the ATN ThOR 4 640 thermal scopes.

1. Extra-long Detection Range 

The ATN ThOR 4 640 has one of the longest detection ranges of any thermal scope. The highest magnification lens with a zoom between 4x and 40x can detect human-sized prey from as far as 3,300 yards, making it easy to track animals from afar.

The identification range is closer but still an impressive 800 yards.

2. 640x480 Resolution

The ATN ThOR 4 640 offers the highest resolution found in thermal scopes, 640x480. More pixels allow the ATN ThOR 4 640 to gather more thermal information from the environment.

You’ll see targets in better detail, even during the day when there is less temperature difference between targets and the background.

The high resolution allows the scope to detect animals as far away as 3,300 yards and provide a zoom as high as 40x.

With lower resolution scopes, image quality deteriorates quickly when you zoom.

3. HD Display with Multiple Color Palettes 

Forget fuzzy and grainy displays that distort what you are seeing. The 1280x720 HD display on the ThOR 4 640 scope displays crisp and sharp images.

Even when you zoom, the image remains relatively sharp with minimal distortion.

Like other thermal scopes, you can cycle through different color palettes for a better view of your target. Options include white hot, black hot, and color mode. 

4. One-Shot Zero Sighting 

Zeroing a rifle scope is essential for shooting accuracy. This process is easy and quick, with the ThOR 4 640.

You only need to take a single shot to sight the scope, hence the name one-shot zero sightings. This ensures you are ready to hunt in no time.

5. Ballistic Calculator 

atn thor 640

Accuracy is not all about zeroing your scope. When you are out in the woods, a wide range of factors, including wind, temperature, and humidity, affect your shot accuracy.

To increase your chances of dying on shots every time, the ThOR 4 640 comes with a built-in ballistic calculator.

The ballistic calculator takes a bunch of data and uses it to automatically adjust the reticle. Some of the data, like barometric pressure, is measured automatically from the internal sensor.

Other data points like temperature and relative humidity require manual entry. You’ll also need to enter your rifle and ammunition’s information, including drag function, bullet weight, and initial velocity.

If you have multiple rifles, you can have separate profiles for each, so you don’t need to enter the information every time you switch rifles.

The ballistic calculator replaces complicated charts and calculations. It also saves you the inconvenience of using a separate ballistic calculator app or software.

The ATN ThOR 4 640 does all the calculations for you and sets the reticle at the right spot.

6. Smart Rangefinder 

A laser rangefinder is the most accurate way of calculating distances to targets. If you don’t have one, the ThOR 4 640 has a built-in smart rangefinder.

The ballistic calculator uses information from the rangefinder to center the reticle.  

7. Smart Mil-Dot reticle 

The smart mil-dot reticle further improves shooting accuracy. The reticle makes it easy to choose the best holdover position, compensating for bullet drop because of gravity.

You can also use the mil-dot reticle to calculate approximate range to your target, though you don’t need to since the smart rangefinder does that for you. Trijicon has a helpful blog post on how to use a mil-dot reticle to calculate the range.

Unlike most mil-dot reticles that only work at specific magnifications (usually the base or highest zoom), the smart reticle in the ThOR 4 640 is dynamic.

The reticle adjusts the mil points as you zoom in on your target, as shown below.

Another great thing about the smart mil-dot reticle is that you can use it with the ballistic calculator (another advantage of having a built-in ballistic calculator instead of a separate one).

The ballistic calculator crunches the numbers for you and automatically shows you where to place your holdover using a teal dot. 

8. Dual Video Streaming & Recording with RAV

This is a new feature in the ThOR 4 series. With the ATN ThOR-HD series, you could record video and stream it, but not both at the same time.

With the new Obsidian Core, the ThOR 4 640 can stream live video via the Obsidian app while also recording to an SD card. You don’t have to choose between recording important moments and sharing them live with other people.

What’s even more impressive is that the scope can record and stream HD video. The video resolution is 1280x960 at a frame rate of 60 fps. The high frame rate is handy when recording a moving target. `

To make sure you don’t forget to record the most exciting moments, the ThOR 4 640 has recoil activated video or RAV.

When you turn RAV on, the scope will save a video recording from a few seconds before, during, and after the shot. Video recording is triggered by your rifle’s recoil, and you can adjust how long it records before and after the shot.

To make sure your rifle’s recoil is powerful enough to trigger RAV, the ThOR 4 640 has a RAV calibration feature in the settings. 

9. 16+ Hours Battery Life

With all these awesome features, battery life surely must be terrible?

Surprisingly, it’s better than in other scopes with fewer features. The lithium-ion battery provides at least 16 hours of continuous use.

The battery is bigger than in other scopes, but that’s not the only reason it lasts longer. The new dual-core processor, though powerful, runs cooler and more efficiently.

ATN ThOR 4 640 Lens Options

ATN ThOR 4 640 Lens Options

The ATN ThOR 4 640 is available with four lens options, each with a different magnification range. Here are the four lenses with the detection, recognition, and identification ranges for each.

  • 1-10x (cheapest) – 830y detection, 350y recognition, 225y identification
  • 1.5-15x – 1050y detection, 530y recognition, 330y identification
  • 2.5-25x – 1950y detection, 800y recognition, 475y identification
  • 4-40x (most expensive) – 3300y detection, 1450y recognition, 800y identification

ATN ThOR 4 640 Product Specifications


  • Resolution: 640x480
  • Detection range: Depends on lens (max 3300 yards)
  • Refresh rate: 60Hz
  • Display resolution: 1280x720
  • Video recording: Yes at 1280x960 @ 60 fps
  • Video streaming: Yes
  • SD card max capacity: 64GB
  • Weight: 2.35bs (with 4-40x lens)
  • Operating temperature: -20°F to +120°F
  • Warranty: 3 years

How Easy is it to Use?

If you have used a thermal rifle scope before, it should be easy to get started with the ATN ThOR 4 640. If this is your first thermal scope, there’s a bit of a learning curve.

Because the ATN ThOR 4 640 has so many features, we recommend taking your time to go through the manual and going through the menus and settings.

Learn how to mount the scope on your rifle and zero it. Also, get familiar with the video recording and streaming settings before you go out to hunt.

You don’t want to miss an important moment because you are fumbling around in the menu to find the record button.

Overall, it takes more time to get started with the ATN ThOR 4 640 compared to cheaper scopes. Even experienced hunters will need time to get used to the new features.

But once you know your way around the scope, you’ll discover it’s easier to use than other scopes. Features like the ballistic calculator, smart rangefinder, and smart mil-dot reticle make hunting much easier and more accurate, especially for beginners.

Pros and Cons of the ATN ThOR 4 640 Thermal Rifle Scope


  • Excellent optics.
  • Long detection range.
  • Multiple lens options.
  • Built-in rangefinder and ballistics calculate increase shot accuracy.
  • HD video recording & streaming.


  • Expensive.
  • Takes time to know how to use all the features.

Scope Similar to the ATN ThOR 4 640: Pulsar Thermion XP38

Pulsar Thermion XP38

Like the ATN ThOR 4 640, the Pulsar Thermion XP38 is designed for hunters looking for a high-performance thermal scope and don’t mind paying more to get top of the line optics.

The two rifle scopes are in the same high price range though we think the ATN ThOR 4 640 offers more value for your money.

Here’s how the two scopes compare on important features and specs.


ATN ThOR 4 640

Pulsar Thermion XP38

Thermal resolution



Detection range

3300y with the 4-40x zoom lens; 1050y with the 1.5-15x lens

1500y (1.5-12x lens)

Display resolution



Frame rate

60 Hz

50 Hz

Video resolution



Video streaming




SD Card (max 64GB)

16GB internal storage


2.35bs (with 4-40x lens)



3 years

3 years

As you can see, the ATN ThOR 4 640 outmatches the Pulsar Thermion XP38 on most specs, for roughly the same price.

As we mentioned above, the ATN ThOR 4 640 is the best value for money. It’s more powerful, has better optics, and has more features.


atn thor 4

Looking to upgrade your ATN ThOR 4 rifle scope? Here are the best accessories from ATN.

  • ATN ABL Laser Range Finder with Bluetooth for accurately calculating distances to targets. It attaches to the ATN ThOR 4 scope.
  • ATN Quick Detach Mount that can be moved from rifle to rifle without losing zero.
  • ATN X-Trac Remote Control with Bluetooth gives you an easy and convenient way to use the ThOR 4’s menu. Has buttons for moving through menu options, zoom, and video recording.
  • ATN 20,000mAh Battery Pack gives you an extra 22 hours of continuous use. Combined with the 16-hr built-in battery, you can go hunting for days without requiring a recharge.

Where to Buy The ATN ThOR 4 640?

About the Author Rob Carson

I work in commercial construction, in Dallas, TX.

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