Sig Sauer Electro-Optics SOSBDX4611 Sierra4 BDX Black 6-24x50mm, 30mm Tube Illuminated BDX-R2 Ballistoc w/194 LEDS Reticle

The Sig Sauer Sierra4 BDX is a 6-24x50mm rifle scope built for long-range hunters and precision shooters who want ballistic calculations built into their optics. This 30mm-tube scope connects wirelessly to compatible Sig Sauer KILOBDX rangefinders, pulling real-time distance, ballistic data, and environmental conditions to display an exact holdover dot on its illuminated reticle—no mental math, no guessing at wind and drop. If you're serious about distance shooting and already running a Sig rangefinder, this scope cuts the gap between data and trigger pull.

The heart of the Sierra4 BDX is its digital focal plane reticle: 194 individually controlled LEDs arranged as the BDX-R2 ballistic reticle, giving you crisp aiming points and flexibility you won't find in traditional glass. The scope houses SmartBDC onboard, so you can load up to 9 factory ballistic profiles or create custom ones for your exact rifle-ammunition combination. Whether you're hunting elk at 300 yards or testing precision at the range, the reticle adjusts to your setup—not the other way around. Bluetooth connectivity reaches out to about 30 yards, practical for shooter-spotter teams or repositioning between shots.

Optically, the Sierra4 BDX delivers the clarity you expect from Sig: up to 95% light transmission, waterproof construction (IPX7 rating), and a wide magnification range from 6x to 24x to cover both close-range hunting and true long-distance work. The 50mm objective pulls in light across varied conditions, and the 30mm tube provides plenty of adjustment room—over 48 MOA of travel in both elevation and windage. It's built to take hard use in the field without compromise.

This is a scope for hunters and shooters who value precision and are willing to invest in the ecosystem—the rangefinder pairing is where the Sierra4 BDX truly shines. If you're running a KILOBDX and want ballistics on-glass with battlefield-tested durability, this scope earns its place in your kit.

Key Features

• BDX Ballistic Data Xchange technology pairs with KILOBDX rangefinders to calculate and display exact holdover dots using real-time ballistic and environmental data
• BDX-R2 digital reticle with 194 individually controlled LEDs on digital focal plane for precise aiming in variable light
• SmartBDC onboard allows 9 factory ballistic profiles or fully customizable setups for your rifle and load
• Bluetooth connectivity (up to ~30 yards) for seamless rangefinder-to-scope data transfer
• 6-24x magnification and 50mm objective for hunting and long-range precision work
• 30mm main tube with >48 MOA elevation and windage travel for extended-range holdovers
• Waterproof (IPX7) and optimized optical system with up to 95% light transmission
• Digital focal plane reticle with illumination for low-light and high-contrast shooting

Specifications

Frequently Asked Questions

Does the Sierra4 BDX work with other rangefinders, or only Sig KILOBDX models?

The BDX ballistic data exchange is designed to work with Sig Sauer KILOBDX rangefinders. The scope connects via Bluetooth to receive ballistic calculations from those units. Compatibility with other rangefinder brands is not supported by this system.

What do the 194 LEDs in the reticle actually do?

The BDX-R2 reticle has 194 individually controlled LEDs arranged on a digital focal plane. These allow for bright, precise aiming points and enable the scope to display specific holdover dots calculated by the ballistic data exchange system. The LEDs are powered by two CR2032 batteries.

Can I use the Sierra4 BDX without a rangefinder, or do I need the KILOBDX?

The scope can function without a rangefinder—you can load up to 9 onboard ballistic profiles and use the SmartBDC feature to dial holdovers manually, just like a traditional scope. However, the real-time ballistic calculation feature that makes the Sierra4 BDX unique requires a paired KILOBDX rangefinder.

What's the eye relief on this scope?

Eye relief ranges from 3.24 inches at 6x magnification to 2.44 inches at 24x magnification, which is considered low eye relief. Keep this in mind when setting up your rifle to avoid scope bite during recoil.

Is a scope mount included with this scope?

No, a mount is not included. You will need to purchase a 30mm scope ring and base separately to attach the Sierra4 BDX to your rifle.