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SIG Sauer BDX System

For those who embrace technology, the SIG Sauer BDX system is a great option.

SIG Sauer BDX System
The SIG Sauer BDX system has streamlined the process by utilizing Bluetooth technology so your smartphone, rangefinder and optic remain in constant communication.

Smartphone technology has reinvented every aspect of our lives, and that includes target shooting and hunting. SIG Sauer has been at the forefront of the electro-optics movement, and the company’s line of BDX (Ballistic Data Xchange) equipped scopes and rangefinders have streamlined the shooting process by providing instant access to ballistic data through the use of smart-optics technology.

Ballistic software is useful to shooters, but it’s only valuable if you can access the information quickly and easily. SIG has streamlined the process by utilizing Bluetooth technology so your smartphone, rangefinder and optic remain in constant communication, and the company has made the process simple and straightforward even for shooters who don’t consider themselves particularly tech-savvy.

I would include myself in that group, and I’ll admit I was a bit overwhelmed by the notion of managing communications between two separate optics and my phone and then using the data to try and make an ethical and accurate shot quickly. But, to their credit, the team at SIG’s electro-optics division has made using the BDX system fast and simple. If you can pair your smartphone with your car’s audio system you can probably pair your optics without any issues.

The system works like this. After purchasing your rangefinder and scope, download SIG’s BDX app from the App Store or Google Play. The rangefinder I tested was SIG’s Kilo1800 BDX 6x22 ($480) and the company’s Sierra3 BDX 4.5-14x44 scope ($720; $1,080 when the scope and rangefinder are purchased as a package).

With the BDX app installed, the first task is to pair both devices with your smartphone and then bond the rangefinder and scope. Begin by powering on the rangefinder and then pairing to the smartphone, a process that requires inputting a PIN number that appears within the rangefinder.

The Sierra3 BDX riflescope features a side parallax knob that doubles as an illumination-intensity knob.

Next, you’ll need to pair the scope with the app, and as with the rangefinder, the scope must be powered on to do so. When the app locates your scope, simply place the scope’s power setting on the number indicated by the app and the scope will pair with your smartphone. You can pair multiple rangefinders and scopes with the app.

When both the scope and the rangefinder are paired, the important next step is bonding the two optics, and this requires that the rangefinder be in ABU mode. To bond the optics, click on the prompt in the app and the scope and the rangefinder will be linked.

If you’re familiar with basic smartphone function, the process takes no more than a couple minutes, but if you are confused, SIG offers plenty of support. Every page in the app has a help setting that is activated by pressing the question mark icon, and this offers a simple explanation of how to operate the system. There are also several simple-to-follow instructional videos on SIG’s website, so the process is far less daunting than it sounds.

Once the optics are bonded, when you range a target an amber dot on the scope’s reticle will provide a holdover point. You can customize both environmental and ballistic data using the app, and SIG offers an extensive library of loads that includes preprogrammed data for a wide range of bullets. You can customize this load data if you’re reloading, and once you’ve paired your optics and have selected load data, you’ll have access to holdover info.

Having instant access to holdover data is convenient, but SIG has added some extra features that make the BDX optics even more user-friendly. For starters, there’s an inclinometer in the scope that ensures the scope is level when mounting, and you can program wind settings into the app to include wind holds.

Furthermore, you can customize the wind holds to appear on one side of the reticle, both sides, or you can turn off the feature altogether. In fact, you can easily customize just about every aspect of optics function, from changing brightness settings to alternating different modes and switching into power-save mode when the scope battery indicator light shows low power.

With all this technology at a shooter’s fingertips, it would seem—and critics will no doubt cry out—that the SIG Sauer BDX system is going to encourage hunters to take shots beyond the limits of their skill and their weapons, but SIG added an extra feature to this scope known as KinEthics that indicates when a shot is outside your predetermined parameters of your load’s effectiveness. Based on the ballistic data, the holdover point flashes when your bullet’s energy (or velocity, if you prefer) is lower than the threshold to make a clean kill.


Does the system make it impossible to take shots beyond the effective limits of your firearm? No, but it indicates to the shooter that the load they’re firing won’t have sufficient energy at the specified range to make a clean kill. The system can be disabled for long-range target shooting, but to its credit, SIG is making an effort to alert shooters that even though they may be able to hit a target doesn’t necessarily mean they can make a clean kill.

When the Sierra3 BDX riflescope is paired with the Kilo1800 BDX rangefinder, it provides holdover data right in the scope.

In addition to all this user-friendly tech, these optics are well-built. The Kilo1800 BDX offered a clear field of view and easy-to-use controls. There’s a mode button that allows you to manually adjust rangefinder settings—although the app is, in my opinion, easier to use. The unit weighs just eight ounces and measures a bit over four inches, so it’s easy to carry.

The Sierra3 BDX 4.5-14x44mm scope features a 30mm maintube and SpectraCoat lenses, and the holdover dot scales with the zoom level to subtend properly at any magnification setting. There’s a side parallax adjustment knob that shares space with the illumination dial and battery settings, and the scope’s durable aluminum body is built to withstand shock and abuse, protecting the electronics and lenses within. The Kilo1800 BDX runs on a single CR32 battery while the Sierra3 BDX scope operates using two CR2032 batteries.

After pairing the scope and rangefinder with my smartphone, I tested the BDX unit on an E.R. Shaw Mark X bolt-action rifle chambered in 6mm Creedmoor firing Hornady’s 108-grain Match loads. The first step was to zero the rifle at 100 yards (you can adjust zero range in the optics), and when I ranged the target, I received an immediate response from the scope.

From there, I moved back to 200 and 300 yards, the maximum distance at my range, and used the system to place shots at those ranges. At 200 paces the group measured around an inch and was spot on, and at 300 yards the group size was roughly 2.5 inches and a single 108-grain bullet passed through the center of the bullseye. At that range, the KiloEthics feature indicated the bullet would drop below the preset 1,500 ft.-lbs. energy threshold, just as advertised.

For those who embrace technology, the BDX system is a great option. And with a suggested retail price of just over a grand for the scope/rangefinder combo, I’d say this is an affordable entry into the world of electro-optics, especially considering the level of technology and the relative ease of use. Once you set up this system, it is intuitive and is ideal for hunting in areas where you may have to make a long shot and don’t want to have to try to determine dope on the fly.

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