Trijicon TA31RCO M4CP ACOG 4x32 USMC RCO Riflescope M4 M4A1 TA31RCO M4CP UPC 719307302075

Product Description

The Trijicon TA31RCO-M4CP ACOG® 4x32 USMC Rifle Combat Optic (MPN: TA31RCO-M4CP / SKU: 100230) is an iconic, combat-proven optical sight engineered specifically for the United States Marine Corps for deployment on M4 and M4A1 carbine platforms. Built to rugged military specifications, this 4x fixed-magnification optic incorporates Trijicon's proprietary dual-illumination system—utilizing fiber optics for bright daytime reticle illumination and tritium phosphor for continuous, battery-free low-light and night performance.

Precision-molded and housed in a forged 7075-T6 aircraft-grade aluminum alloy chassis, the TA31RCO-M4CP is designed to withstand extreme thermal shock, impact, and immersion in water up to 11 meters. It features a specialized dual-illuminated Red Chevron reticle w/ bullet drop compensation (BDC) target ranges calibrated specifically to the ballistic trajectory of 5.56x45mm NATO 62-grain M855 ammunition fired from a 14.5" barrel. The reticle includes integrated target width ranging stadia lines to enable rapid target distance estimation and holds out to 800 meters.

Designed around the Bindon Aiming Concept™ (BAC), the 4x32 ACOG allows shooters to keep both eyes open while tracking target schedules, facilitating immediate close-quarters transition alongside fixed 4x optical magnification. Complete with a TA51 Picatinny thumbscrew mount, a TA91 killFLASH® Anti-Reflection Device, and a protective neoprene scope cover, the TA31RCO-M4CP delivers legendary battle-proven reliability.

Armorer Bench Notes & Real-World Staging Guidance:
Fitment Matrix: Mounts to any standard MIL-STD-1913 Picatinny rail via the included TA51 mount. Reticle BDC is factory-calibrated for 5.56 NATO 62-grain (M855) out of 14.5" M4 carbine barrels, though it performs exceptionally well with 16" carbine setups with minimal trajectory variance.

1. Perform a complete firearm safety check: drop the magazine, lock the bolt rearward, and visually/physically inspect the chamber to verify zero live rounds are present.
2. Clean and degrease the receiver top Picatinny rail slots using isopropyl alcohol or thread prep cleaner.
3. Place the TA31RCO-M4CP with attached TA51 mount onto the receiver rail, pushing forward toward the muzzle to seat the cross-bolts firmly against the rail recoil slots.
4. Hand-tighten the thumb nuts, then torque to 45 in-lbs using a torque wrench or coin/screwdriver to prevent loosening under heavy recoil.
5. To prevent reticle bloom in direct sunlight, apply a small strip of electrical tape or adjustment flip-cover over a portion of the top fiber optic light pipe to adjust daytime brightness to your environment.
6. Zero the optic at 100 meters using the tip of the red chevron reticle per military staging procedures.

Key Features

• Battery-Free Dual Illumination: Fiber optic cable automatically adjusts reticle brightness in daylight; tritium lamp illuminates reticle in total darkness.
• USMC Calibrated BDC Reticle: Red Chevron BDC reticle calibrated for 5.56 NATO M855 ammo fired from 14.5" M4 carbine barrels out to 800 meters.
• Bindon Aiming Concept™ (BAC): Facilitates dual-eye-open targeting for rapid close-quarters acquisition and situational awareness.
• Forged 7075-T6 Aluminum Housing: Military-spec alloy housing engineered for extreme durability under harsh combat conditions.
• Waterproof & Nitrogen-Filled: Dry nitrogen purged to prevent internal fogging and waterproof submerged up to 11 meters (36 feet).
• Includes TA91 killFLASH® & Accessories: Complete with anti-reflection device, TA51 Picatinny mount, and protective scope cover.

Product Specifications

• Brand: Trijicon
• Model/Series: ACOG® 4x32 USMC RCO (M4 / M4A1)
• MPN / SKU: TA31RCO-M4CP / 100230
• UPC: 719307302075
• Magnification: 4x
• Objective Lens Diameter: 32mm
• Reticle Pattern: Dual-Illuminated Red Chevron w/ BDC & Ranging Stadia
• Illumination Source: Fiber Optics & Tritium
• Caliber / Barrel Calibration: 5.56x45mm NATO / 14.5" Barrel (M855)
• Eye Relief: 1.5 Inches
• Exit Pupil: 8.0mm
• Field of View: 36.8 ft @ 100 yards (7.0 degrees)
• Housing Material: Forged 7075-T6 Aircraft Aluminum
• Finish / Color: Matte Black Hardcoat Anodized
• Mount Type: TA51 Mount (MIL-STD-1913 Picatinny)
• Dimensions (L x W x H): 6.7 in x 2.1 in x 2.6 in
• Weight: 9.9 oz (15.8 oz w/ Mount & killFLASH)
• Country of Origin: USA

INCLUDES

• Thumbscrew Flattop Adapter (TA51)
• killFlash Anti-Reflection Device (TA91)
• Scopecoat (TA96)
• LENSPEN (TA56)
• Lanyard Assembly for Adjuster Caps (TA71E)
• Trijicon Logo Sticker (PR15)
• RCO Manual
• Warranty Card