Range and Record: ATN’s ThOR 5 640 LRF 4-32X Thermal Riflescope

Among thermal riflescopes offering a triple play of thermal, ranging and ballistic capabilities is the ATN ThOR 5 640 LRF 4-32X, with the “LRF” denoting the laser rangefinder built into the unit.

June 11, 2025 | by Brian McCombie |

ATN Predator Xtreme

Many of the latest generations of thermal riflescopes come complete with an addition that seemed impossible just a couple decades ago: a built-in laser rangefinder. And not simply a rangefinder for determining distances, but one which, when paired with the right firmware, can produce ballistic solutions for those far-away shots. Pretty amazing.

Among those units offering this triple play of thermal, ranging and ballistic capabilities is the ATN ThOR 5 640 LRF 4-32X thermal scope, introduced to the hunting public at the SHOT Show in January 2023. Previously, ATN Corporation (www.atncorp.com) offered only range-finding with its Auxiliary Ballistics Laser (ABL) accessory for its units, which could be Bluetooth paired and attached to past generations of ThOR thermals.

I had the chance to run the ThOR 5 640 LRF recently, at my outdoor range during the day and then at night to evaluate the unit’s photo and video applications. I also needed to determine just how well the rangefinder worked at night. The ThOR 5 640 LRF featured easy-to-navigate menus, solid photo and videos and a long-life built-in battery for long nights afield. My unit zeroed quickly and produced some very accurate groups. The rangefinder worked great, too, and at night when a hunter needs it the most.

Features and Functions

As the numbers in the name proclaim, the ThOR 5 640 LRF 4-32X is powered by a 640x480 thermal sensor, with digital magnification of 4 to 32X. The unit features a 1280x1024 OLED display and One-Shot Zero, Profile Manager and Recoil Activated Video functions. Power is provided by a built-in, Li-ion battery, which charges through the USB-C port on the right side of the unit. The charging cable is included. ATN rates battery life at 10 hours when fully charged.

Magnification increases or decreases with the Up and Down buttons on the keypad, and the laser rangefinder is located to the front, left of the unit, and activates by simply pressing the Function 1 button on the right bottom corner of the keypad. When that button is pressed, four red lines appear on the screen, coming from the corners to the center. Center the object within those four lines and the rangefinder calculates the distance and presents it at the bottom of the display screen.

As with most thermals, the ThOR 5 has a number of options for reticle types and colors, and color palettes. The unit is also Wi-Fi capable and can take both photographs and videos at a fairly high resolution. A Mini-SD card (not included) stores media and also allows the user to perform firmware updates.

ThOR accessories include an eyecup, a flip-open front lens cap, scope cover, two standard 30mm rings for mounting onto a rail and a USB-C cable, as well as a Quick Start guide and a larger, more detailed user manual.

Zeroing-In the Unit

To try out the thermal, I mounted the ThOR 5 640 LRF onto one of my favorite hunting rifles, a DPMS Hunter GII chambered in .260 Remington. Mounting the thermal took only a few minutes thanks to the two 30mm rings included with the unit.

As with many thermals, the ThOR 5 features an one-shot zeroing system, where the shooter takes an initial shot or two and then adjusts the reticle to the point of impact and saves this information; follow-up shots should be on target. Other units require a shooter to choose between the one shot and the manual zeroing. However, the one-shot system on the ThOR is the zero system.

During the day I tried out the thermal at my outdoor range, it was in the low 60s, but very sunny. To create a heat source, I used a heat pad and affixed it to cardboard backing with black duct tape. Actually, the duct tape heated up much faster than the pad, and the duct tape rectangle became my target for my 50-yard zero.

My first shots were about a foot low and 4 to 5 inches right. I accessed the Zero application and moved the X and Y axis lines onto the area where my first shot impacted. My next shots were much closer to the taped heat packet, but just a little low. One more adjustment via the one-shot zero put me right on target.

’Yote at 100 Yards

Time for some 100-yard shooting. For this, I used a life-size paper coyote target made by Delta McKenzie. Over the heart-lung area of the target, I placed two strips of my black duct tape to form a 3.1- x 3.7-inch heat signature/aiming point. I also applied a single strip of tape over the coyote’s head for a 1.8- x 3-inch aiming point.

First, I took a few shots at a different target at this distance to make sure the ThOR and rifle were on at this distance. It was slightly off, so I made another one-shot adjustment. I then shot the double strip of duct tape six times, the single strip also six times. My ammunition here (and at 50 yards) was Remington Premier Match .260 Rem. loaded with a 140-grain open-tip bullet.

My first six shots hit the black double tape and produced a group of 1.6 inches. One of my “head” shots on the single strip struck just off the left edge of the tape, while the other five shots clustered in at 1.1 inches. The ThOR 5 640 LRF will definitely put a hunter on coyotes and hogs and other varmints and is very capable of doing so at a good distance, too.

Using the Keypad

The ThOR keypad arranges around a center OK button, with the Up, Down, Right and Left buttons positioned in a circle, which is a simple and functional enough setup. But I wished the button pads on the non-OK buttons were raised up a bit. They had very smooth surfaces and my fingertips frequently had trouble finding the correct pads by touch.

Also, the focus adjustment ring at the front of the thermal was very tight, and the laser rangefinder is located alongside the rear of the ring and nearly touching. Those two realities made it very tough to do a quick focus adjustment.

The rangefinder, though, worked well. I used it at known distances and it proved extremely accurate. I also used it in conjunction with a high-quality handheld rangefinder and the two units provided almost exactly the same distances. While I did use the unit’s rangefinder, as noted, I didn’t take shots at longer distances with the aid of the ballistics calculator. However, I did access the calculator app, and entering the ballistic data was a very straight-forward process. Of course, as with any ballistics program, this means the shooter must know the muzzle velocity of the round, the weight of the bullet and its ballistic coefficient, etc.

Once that information is loaded into the onboard ballistics calculator, the hunter only has to range that coyote or hog and the calculator will give real time, onscreen adjustment of the reticle. This eliminates the need for hold-over on longer shots.

Record the Night

I took my ThOR unit out on three separate night-time runs to evaluate photo and video quality and capabilities, and to run the rangefinder under dark conditions. All worked very well. To select either video or photo captures, I long pressed the Left button pad. Then, taking a photo or starting/stopping a video simply required a short press of the same button. The photo and video images were quite clear and were saved on my mini-SD card. I later transferred them to my laptop.

Next, I visited our local zoo, which includes a fenced field that is over 10 acres large and split into smaller units. Near the field sits an observation platform and I set up there for some scanning. I surveyed the field through my ThOR, knowing there were bison, deer and elk in the various sections, but couldn’t pick up any heat signatures with a quick scan. I went back over the area slowly, the palette set on Black Hot and eventually spotted a pair of treetops. But the treetops were very close to ground level. What the heck?

They weren’t trees at all, but the antlers of two bull elk, the pair sitting on the far side of a slight incline. I pressed the button to activate the laser rangefinder: 198 yards. Then, I took photographs. And I could count the tips of the elk antlers, sending out heat into the 65-degree night.

In a world of $6,000 to $10,000 thermal riflescopes, the ThOR 5 640 LRF 4-32X does it all with an MSRP of just over $4,000. Translation: many features at a (relatively speaking) bargain price.

SPECS: ATN ThOR 5 640 LRF 4-32X Thermal Scope

Sensor: 640x480 60 fps 12µm

Magnification: 4-32X

Laser Rangefinder: Yes

Field of view: 8.8°x6.6°

Core: ATN Gen V Quad Core

Display: OLED display 1024x768

Eye relief: 3.5 inches

Video Record Resolution: 1280 @ 60 fps

Ballistic Calculator: Yes

Wi-Fi Capable: Yes

3D Gyroscope: Yes