Trijicon ACOG TA31RCO 4x32 USMC Combat Rifle Scope M16A4

Trijicon ACOG Scope: Mission-Ready Confidence

Trijicon ACOG TA31RCO 4x32 USMC Combat Rifle Scope M16A4 meets you in the chill predawn when batteries quit, turning blurred outlines into crisp hits while you keep both eyes open. This Trijicon ACOG scope—stalwart of the ACOG 4x32 Red Chevron family—fuses forged-aluminum armor with ambient-light glow so you can flow from hallway drills to 800-meter steel. Explore our Combat Optics Guide, compare builds in ACOG vs LPVO, and dial precision with How to Zero an ACOG.

Forged in the USA and backed by a Lifetime Warranty, this optic shrugs off recoil, weather, and fog, giving serious shooters a battery-free edge and unwavering trust.

Built for duty-minded shooters—infantry-clone builders, patrol officers, and 3-gun athletes—the Trijicon ACOG scope’s ACOG 4x32 red chevron turns dawn silhouettes into 800 m hits, earning 4.8★ from 28 verified owners (86% five-star).

If you rely on generous eye relief, shoot primarily inside 50 m, or prefer variable-power glass, this rugged prism may frustrate; 1 in 5 reviewers cite its tight 1.5-in eye box when firing from awkward positions. 

Battery-free tritium/fiber illumination — The Trijicon ACOG scope stays bright in any light, eliminating battery failures during moments. 

Forged 7075-T6 aluminum body — Combat-proven construction shrugs off recoil, shock, and 11 m dives to guard your zero. 

Fixed 4× prism with Bindon Aiming Concept — ACOG 4x32 red chevron optic enables both-eyes-open speed from hallway to 800 m engagements. 

36.8 ft/100 yd field of view — Broad sight picture enhances situational awareness, accelerates threat identification, and supports fast follow-up shots. 

Tool-less windage/elevation turrets & thumbscrew mount — Rapid installs and on-the-fly adjustments simplify zeroing during high-tempo operations.

Strengths: The Trijicon ACOG scope outshines with exceptional glass clarity and legendary durability that "just works" when batteries fail. This ACOG 4x32 red chevron masterpiece couples tritium/fiber illumination with forged 7075-T6 aluminum armor to deliver brilliant sight pictures plus guaranteed zero retention through thousands of rounds, extreme temperature swings, and combat.

Limitations: The TA31RCO's 1.5-inch eye relief demands nose-to-charging-handle positioning that fatigues during extended shooting and restricts head placement options. Fixed 4× magnification also slows close-quarters engagement speeds compared to red dots, requiring most shooters to add offset optics or accept reduced CQB performance.

Trijicon ACOG TA31RCO Combat Scope - Specification Sheet

Trijicon ACOG Scope - Red Chevron Reticle Dimensions

Does the Trijicon ACOG scope need batteries for illumination?
No; tritium and fiber optics power the ACOG 4×32 red chevron aiming point so it stays lit without batteries.

What eye relief should I expect from the ACOG 4×32 red chevron?
About 1.5 inches; keep your nose near the charging handle for a full, bright sight picture.

Can the Trijicon ACOG scope handle harsh weather and heavy recoil?
Forged 7075-T6 housing is waterproof to 11m and shock-tested to 8,000g, withstanding field abuse.

Will the ACOG 4×32 red chevron mount on a flat-top AR?
Yes, it's TA51 thumbscrew base clamps directly to any MIL-STD-1913 Picatinny rail—no rings needed.

What warranty does Trijicon provide for this scope?
Lifetime coverage on the optic; the tritium lamp is guaranteed to glow for fifteen years from manufacture.

Can I add a mini red dot to the Trijicon ACOG scope?
Integrated bosses accept Trijicon RMR or similar micro sights for faster close-quarters transitions.