Trijicon ACOG 4x32 USMC RCO OP1 Dual Illum Red Chevron 100226

If you’re looking to clone a Marine Corps M4 or just want one of the most battle-proven optics ever devised, the Trijicon ACOG USMC RCO (TA31RCO-A4CP) is the gold standard.

Specifically tailored for the 20" barrel of the A4 rifle, this $4 \times 32\text{mm}$ optic is built to handle the absolute worst conditions on the planet while providing surgical precision.

Why It Stands Out

• Dual-Illumination: Uses a combination of fiber optics for daytime brightness and tritium for low-light/night conditions—no batteries required, ever.

• USMC RCO Reticle: Features a red chevron reticle with a Bullet Drop Compensator (BDC) and target-ranging features specifically calibrated for the 5.56 NATO round.

• Bindon Aiming Concept (BAC): Designed to be used with both eyes open, allowing for rapid target acquisition in close quarters while maintaining $4\times$ magnification for long-range shots.

• Ruggedized to the Core: Housed in 7075-T6 aircraft-aluminum, it is nearly indestructible, waterproof, and fog-proof.

Technical Specifications

Pro Tip: While this specific "A4" model is calibrated for 20" barrels, it remains incredibly effective on 14.5" or 16" carbines with only minor shifts in the long-range BDC holds.