Understanding Fiber Optic Reticles

If you’ve spent any time around handguns or shotguns, you have likely seen, shot with, or even installed fiber optic sights. Typically seen as a plastic red or green rod inserted into the pistol or shotgun’s front or rear sight post, fiber optic sights provide a high visibility point of aim in bright conditions thanks to their ability to absorb and reflect light. However, iron sights are not the only use case for fiber optics technology in firearms.

Optical fiber is also used in riflescopes, like the Bright Fiber Optic (BFO) reticle of our second-generation Tomahawk II SFP LPVO, the dual tritium/fiber optic illuminated Trijicon ACOG, and others.

Without getting too technical, let’s review what fiber optics technology – or the application of optical fiber – is and how it works. These concepts will lay the foundation for better understanding fiber optic reticles.

What is Optical Fiber?

Optical fiber is a glass or plastic filament that transmits light – either from an ambient (e.g., the sun) or direct source (e.g., LED emitter) – from one end to the other by total internal reflection. The dense fiber core is clad in a refractive layer that reflects and transmits the confined light through its core until reaching the end of the fiber where all condensed light is released. Because of the concentrating effect of total internal reflection, the emitted light is brighter than both the surrounding light and light source itself.

Simply put, optical fiber draws in light and condenses it through internal reflection before releasing it as ultrabright illumination. Imagine a flashlight shining light down a metal straw, only brighter on the opposite end.

The same technology used in fiber optic telecommunication and computer networking, medical endoscopes, and pre-lit artificial Christmas trees, optical fiber can be rigid or flexible.

Unlike common illuminated scopes with glass-etched reticles, in which a light emitting diode (LED) shines light onto luminescent material to illuminate the reticle design, fiber optic reticles use a thin optical fiber tube to deliver center point illumination from an LED emitter.

Connected to traditional wire crosshairs suspended in the optic body, the end of the optical fiber tube is cut at a 45-degree angle toward the ocular assembly, creating an elliptical shape cross section that resembles a circle to the shooter’s eye when illuminated.

Ultrabright Illumination

Even though fiber optic tubes used in scope reticles are short and hair-thin, fiber optic reticles provide significantly brighter illumination than etched reticles, stemming from the concentrating effect of total internal reflection. As a result, fiber optic reticles provide better performance in low light and daylight bright conditions. However, illumination is limited to a small center point, whereas etched reticles can be larger and more detailed.

Red Dot Simplicity

For shooters seeking point-and-shoot reticles, the single center point illumination of fiber optic reticles offers red dot simplicity in second focal plane (SFP) variable optics. Often accompanied by a thicker wire crosshair that draws the eye to the reticle center, fiber optic reticles can be used with and without illumination depending on light conditions. Best suited for short-to-medium range applications within 200 yards, fiber optic reticles have accuracy limitations at extended distance,

More Color Options

While glass-etched and fiber optic reticles are both illuminated by LED emitters, traditional scopes are typically only offered in red and green illumination. This is partially in response to shooter feedback and consumer demand, but also due to the difficult nature of achieving crisp and clear illumination with other colors. Because optical fiber transmits light directly from an LED emitter, a wider spectrum of reticle colors – like amber, blue, and others – are possible.

Launched with the Swampfox Tomahawk II SFP LPVO, the Bright Fiber Optic (BFO) reticle is our brightest reticle yet. Using high-efficiency optical fiber technology, the BFO delivers nuclear bright center point illumination for shooting in any light against any background. Available in four reticle colors, choose between standard red or green illumination, or new amber and blue options.

Paired with the generous eye box and superior glass quality of the second-generation Tomahawk II, the bright and versatile BFO reticle complements a quick sight picture for speed and precision on the range and in the field. Minute of Angle (MOA) ranging with 5 MOA subtensions provide accurate holdovers to compensate for bullet drop and wind shift, while a CR2032 battery powers 12 brightness settings with intermittent on/off positions.

Shop Swampfox Tomahawk II

Historically, fiber optic reticles have been more expensive to produce than glass-etched lenses, limiting their use to a handful of optics or those with higher price points. However, as optical fiber technology and manufacturing techniques continue to improve, some manufacturers – like Swampfox – are bringing fiber optic reticles to budget-friendly optics.

Below are optics currently on the market with LED-powered fiber optic reticles:

Swampfox Optics

• Tomahawk II 1-4x24x / Bright Fiber Optic (BFO)
• Tomahawk II 1-6x24x / Bright Fiber Optic (BFO)

Hawke Optics

• Vantage 30 WA FD IR 1-4x24 / L4A Fiber Dot
• Vantage 30 WA FD IR 1-8x24 / L4A Fiber Dot
• Vantage 30 WA FD IR 2.5-10x50 / L4A Fiber Dot
• Vantage 30 WA FD IR 3-12x56 / L4A Fiber Dot

Leupold

• Mark 3HD 1.5-4x20 / FireDot SPR
• Mark 3HD 1.5-4x20 / FireDot BDC
• Mark 3HD 1.5-4x20 / FireDot TMR
• Mark 4HD 1-4.5x24 / FireDot BDC
• Mark 4HD 1-4.5x24 / FireDot TMR
• Mark 3HD 3-9x40 / FireDot TMR
• Mark 3HD 4-12x40 / FireDot TMR
• VX-Freedom 3-9x50 / FireDot Twilight Hunter
• VX-3HD 1.5-5x20 / FireDot Twilight Hunter
• VX-3HD 3.5-10x40 / FireDot Twilight Hunter
• VX-3HD 3.6-10x50 / FireDot Twilight Hunter
• VX-3HD 4.5-14x50 / FireDot Twilight Hunter

Monstrum Tactical

• Banshee 1-6x24 / BDC-C1

Primary Arms

• SLx 1-6x24 Gen IV / ACSS Nova MIL
• SLx 1-6x24 Gen IV / ACSS Nova BDC

SIG Sauer

• Canyon 4-16x44 / Hellfire Ballistic Hunter BDC
• Tango-DMR 3-18x44 / MOA Milling Hellfire
• Tango6 1-6x24 / MOA Milling Hellfire
• Tango6T 1-6x24 / Hellfire DWLR-556
• Whiskey4 3-12x44 / BDC-1 Hellfire

Vector Optics

• Constantine 1-6x24i / Fiber Dot

Vortex Optics

• Razor HD Gen II 1-6x24 / JM-1 BDC
• Razor HD Gen II 1-6x24 / VMR-2 MOA
• Razor HD Gen II 1-6x24 / VMR-2 MRAD
• Viper HD 3-15x44 / VMR-3 MOA
• Viper HD 3-15x44 / VMR-3 MRAD
• Viper HD 5-25x50 / VMR-3 MOA
• Viper HD 5-25x50 / VMR-3 MRAD

This article was last updated in May 2024.