Hot property
Burris thermal scope no budget-buster, says Matthew Godson
My first impressions of the Burris BTS35 V2 thermal scope as I lifted it from the box was that it certainly looked and felt rugged in design. In the hand with mounting system and batteries installed, it weighed around 940 grams and an American Defense quick-detach Picatinny mount is included, which saves you a few hundred dollars. This also means flexibility to easily switch your scope from one firearm to another and maintain reasonable zero while doing so.
Ergonomically, everything you need is comfortably in reach and there are only three function controls ‑ the power button, menu button and rotary knob. Once the device is on the power button also controls shutter calibration, the menu button is pressed to display options and you make the selections you want by turning the rotary knob. When not in menu function this knob decreases and increases digital zoom.
The features and specifications of the BTS35 V2 are impressive for a thermal scope at this price point, with a 35mm F1.0 lens that provides clear images on a 1024 x 768 OLED display. For the tech-minded, it comes with a 400 x 300 VOx thermal sensor offering a reasonable ≤50 mK NETD, a pixel pitch of 12 microns and 50Hz refresh rate. With these specifications the scope produces thermal images that’ll remain relatively sharp during movement when tracking targets and detecting temperature differences at longer ranges. It offers a generous and wide field of view of 7.8° x 5.9° and claimed detection distance of 1000m for a deer-sized animal.
With a base magnification of 3.2x expanding to 12.7x with 1-4x digital zoom, the scope will handle most shooting situations at short to medium range and offers five colour palettes including white hot, black hot, red hot, green hot and blue hot. It has picture-in-picture (PIP) mode which gives the user an option to position the PIP window in the upper left, middle or right of the display. There’s also auto stand-by, auto power off and energy-saving modes. Stand-by can be set to off, five, 10 or 15 minutes and auto power to off, five, 30 or 60 minutes with these features helping maximise battery life in the field.
The BTS35 V2 has 10 reticle options and you can adjust the colour of those and illumination to suit your needs, the choice of reticle base colours including red, green, blue, black, white and yellow. Users can select a centre or cross-dot illumination point that’s separate from the base reticle and that centre dot or cross colour can also be changed to any of the above colours.
The scope offers a stadiametric rangefinder to estimate distance with four stadia target options available as a reference being rabbit, coyote, hog and deer. The way this function works is you align the lower horizontal line with the bottom of the target, then use the rotary knob to change the width between the upper and lower horizontal lines until the upper is aligned with the top of the target. The scope will then automatically calculate and display an estimated distance based on the size of the reference animal.
The scope comes with an internal 18650 battery and a second replaceable one for five-plus hours of runtime. That extra battery allows the flexibility of having spares to hot-swap during activities to extend your runtime in the field, while connecting to a power source via the USB cable enables live charging of the internal battery. Real-time video streaming and photo capture is available on the BurrisConnect app and as the device doesn’t have memory, all recorded activities need to be stored that way. This also allows you to make changes to device settings so you can adjust palette colour, operate the stadiametric rangefinder, tweak contrast, hotspot tracking, PIP and more.
The first job with any new scope is to set up zero and the BTS35 V2 has a set minimum 50m zeroing distance value so that’s where you start. Depending on the size of your target you may need to fire a few shots at short distances to make sure point of aim (POA) and point of impact (POI) are both ‘on paper’ so to speak. This scope doesn’t have a freeze function so you must record measurements of POI compared to POA to make the necessary adjustments.
The best way to do this is fire a group of three shots while aiming at the middle of the target. Measure the vertical and horizontal distance between group centre and target centre and, using the rotary knob, make the necessary elevation and windage adjustments (in millimetres) by clicking through the right amount of modification equal to your recorded measurements. Once changes are saved, shoot again to make sure zero is achieved (this process must be repeated for all profiles you save on the scope).
Generally when using a 22LR rifle I sight-in at 25m, though on this occasion I had to push it out to 50m to fit the device’s minimum zeroing distance so the stadiametric rangefinder would be effective. With zeroing complete I test-fired on a target at 25m and was happy with the result, confident any rabbit up to 75m that dared to show itself would be within my target range.
Not having built-in memory, picture/video button and auto-recording functionality does make it a little tricky to capture images of your activities. Having to operate a device while trying to engage targets is difficult if you don’t have time on your side, though generally speaking working in the dark with thermal gives you that time. Having your phone connected to the app before you start lets you quickly press ‘record’ to capture the moments you want.
Tackling a few rabbit populations on small blocks, the BTS35 V2 proved an effective and easy-to-use device. The field of view offered plenty of visibility to scan paddocks and vegetation as I walked, while the zoom function brought more distant targets close enough to identify and engage with if necessary. It was comfortable to operate with one hand and the rotary knob allowed easy zooming in and out using fingertips, with both the focusing ring and diopter adjustment being smooth in operation.
All palette choices provided good images of both landscape and targets alike. You can activate the ‘hot track’ function or change scene modes to highlight objects with the highest temperature to help find potential targets dependent on conditions. A handy function if temperature differences between day and night aren’t extreme is leaving background heat in the landscape. Reticle choices and options are the individual’s choice and with what’s on offer there will probably be several you’ll take a fancy to.
When targeting rabbits at distances of around 50m, I found images produced by the sensor through the F1.0 lens and OLED display to be fairly crisp for a unit with a ≤50 mK NETD. It certainly isn’t the most sensitive thermal sensor on the market but it’s reasonable quality at a sensible price. I do enjoy testing thermal devices on small targets such as rabbits because the output can only be better on bigger animals with larger thermal signatures. If you can clearly see a rabbit at 50m there’s no doubt you’ll spot larger targets at ranges beyond 150m.
To prove this point I viewed and captured images of horses in paddocks at ranges between 100-150m and one thing I did notice is that what you see through the eyepiece is much better quality than any saved images. For example, the rabbit I captured was less pixelated in appearance through the eyepiece to the point where I could clearly see its ears as it moved around. That crispness wasn’t evident in the recorded images and I could also see far more detail in the horse’s bodies through the eyepiece than in stored images.
During testing I removed the scope from the rifle several times since my initial zeroing and found that upon reattachment it retained adequate zero. This gave me confidence that the inclusion of the American Defense quick-detach Picatinny mount will help provide flexibility and consistency straight out of the box for anyone buying a BTS35 V2 thermal scope. Burris warrants its thermal optics are free of defects in workmanship and materials for three years from date of purchase. RRP of the Burris BTS35 V2 is around $3799.