Trijicon ACOG 4x32 Rifle Scope Chevron .223 BAC Red Reticle – TA31F

The Trijicon ACOG 4x32 Rifle Scope Chevron .223 BAC Red Reticle (SKU TA31F) is a fixed 4x magnification, 32 mm objective prism rifle scope with an etched chevron bullet drop compensating reticle calibrated for .223/5.56, illuminated in red by fibre optics and tritium with no battery of any kind.

Trijicon designed the ACOG — Advanced Combat Optical Gunsight — for military service, and the features that came out of that programme are the reason the range still sells: the reticle is etched into the prism rather than projected, so it cannot fail; a fibre-optic light pipe along the top of the housing feeds daylight into the reticle and self-adjusts to ambient brightness; and a sealed tritium lamp keeps the same aiming point lit after dark. That heritage is engineering, not marketing — a forged aluminium body, a waterproof seal and nothing to switch on.

Bindon Aiming Concept (BAC): the illuminated reticle is bright enough that, shot with both eyes open, your brain merges the magnified image from the sighting eye with the unmagnified view from the other. You get 4x magnification for the shot and something close to 1x situational awareness for everything around it.

Illumination Colour: Red — this configuration is also stocked as the Trijicon ACOG 4x32 rifle scope Chevron .223 BAC Green reticle.

How It Compares

The reticle pattern is the choice to make here. This is the Chevron, which gives you a chevron tip as the primary aiming point, which gives a fine, unobstructed point of aim and doubles as a ranging reference. The alternatives on the same 4x32 body are the ACOG 4x32 Crosshair Red reticle and the ACOG 4x32 Horseshoe/Dot Red reticle. Want more eye relief and a wider objective? The Trijicon ACOG 3.5x35 rifle scope Chevron Red reticle is the longer 3.5x magnification, 35 mm objective ACOG, and it is the model Trijicon also calibrates for .308/7.62. This same reticle is also sold as a factory package with a Trijicon RMR red dot fitted on top — the ACOG 4x32 Chevron Red reticle with RMR red dot sight (TA31-D-100549). To piggyback your own RMR above an ACOG that has mounting bosses, the Trijicon RM35 RMR mount for ACOG (AC32007) and Trijicon RM66 RMR mount for ACOG (AC32029) are the Trijicon mounts for it. See the whole range in Trijicon ACOG rifle scopes, the optics for straight-pull rifles, the wider prism scope range and the full Trijicon optics range, or read our guide to prism scopes and Trijicon buyer's guide.

Ideal For

• Civilian Service Rifle and practical rifle shooting on a straight-pull AR-pattern rifle in .223/5.56
• Straight-pull carbine work from gallery distances out to 300 m, where one fixed 4x magnification has to cover both ends
• Shooters who want a compact magnified optic with no battery to check, charge or replace before a shoot
• Airsoft and milsim builds replicating an issued rifle, where the ACOG 4x32 is the recognisable optic

Key Features

• Reticle: BAC .223 Chevron — etched into the prism, calibrated for .223/5.56, Red illumination
• Illumination: Fibre optic and tritium, battery-free — daylight feeds the fibre and tritium lights the reticle in darkness
• Magnification / Objective: 4x magnification, 32 mm objective, fixed power
• Aiming Concept: Bindon Aiming Concept (BAC) for both-eyes-open shooting at magnification
• Eye Relief: 1.5 in (38 mm)
• Field of View: 36.8 ft at 100 yards (12.3 m at 100 m)
• Housing: Forged aluminium, waterproof
• Origin: Made in USA

Technical Specifications

What's Included

• Trijicon ACOG 4x32 rifle scope (TA31F)
• Integrated mount
• Lens covers
• User manual
• Warranty documentation

Warranty

Covered by Trijicon's manufacturer's warranty. Keep your order confirmation as proof of purchase and register the optic with Trijicon after fitting; we handle warranty claims for you from the UK.

UK Delivery & Support

UK-stocked and dispatched tracked from our UK warehouse — no import duties or customs delays — backed by UK-based support and Trijicon's warranty.

Frequently Asked Questions

Does the Trijicon ACOG 4x32 need batteries?
No — the Trijicon ACOG 4x32 rifle scope is battery-free. A fibre-optic light pipe along the top of the housing collects ambient daylight and feeds it into the etched reticle, and a sealed tritium lamp illuminates the same reticle in darkness, so there is no battery to fit, replace or find flat.

What is the Bindon Aiming Concept (BAC) on a Trijicon ACOG?
The Bindon Aiming Concept (BAC) is Trijicon’s name for shooting an illuminated ACOG with both eyes open. The reticle is bright enough that the brain favours the magnified sighting eye for the aiming point while still using the unmagnified view from the other eye, so you keep close-range speed and situational awareness at 4x magnification.

Which calibre is this ACOG reticle calibrated for — .223 or .308?
This Trijicon ACOG 4x32 (TA31F) is calibrated for .223/5.56: the bullet drop compensating stadia below the chevron aiming point correspond to that cartridge. Trijicon calibrates the ACOG for .308/7.62 in the larger 3.5x35 body instead — see the Trijicon ACOG rifle scopes collection.

What is the eye relief on the Trijicon ACOG 4x32?
The Trijicon ACOG 4x32 has 1.5 in (38 mm) of eye relief. That is short by rifle scope standards and typical of a compact prism optic, so it wants a consistent cheek weld and a mounting position that puts your eye close to the ocular.

Can I mount a red dot sight on top of a Trijicon ACOG 4x32?
Yes, on ACOG models that carry mounting bosses: the Trijicon RM35 (AC32007) and the Trijicon RM66 (AC32029) are the Trijicon mounts that piggyback an RMR above the ACOG, matched to your ACOG model. This reticle is also sold ready-built as the ACOG 4x32 with RMR red dot sight (TA31-D-100549).

What happens to the aiming point if the illumination is not visible?
The reticle is etched into the prism glass rather than projected, so the full chevron aiming point and its bullet drop stadia remain black and usable against a bright background even when the tritium and fibre-optic illumination is not contributing.