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Questions & Answers
Is this scope design for a 16” barrel on an Ar15, 556, 223 Featured Answer

Yes. This is the same optic I used in the USMC and it's meant for 5.56mm(.223). It doesn't matter if you have a 20 inch barrel or a 14.5" or a 16". Dial it in and you're good to go.

by jaltrx, Verified Owner, April 7, 2018
Does this include the lugs to mount an RMR? Some pictures don’t include them. Expert Answer

No. The Trijicon TA31RCO-M4 ACOG 4x32 USMC M4 Rifle Scope will include:
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

by Ethan, Gear Expert, November 30, 2022
Customer Reviews
Helpful Positive Review
TA31RCO-M4 ACOG by Tyler, Verified Owner, November 6, 2024
USMC ACOG showed up in a timely manner with no issues. The new style ACOGs do come with the rear lugs to piggy back a red dot I hadn’t seen that mentioned in previous reviews
1/1 found this helpful
Helpful Positive Review
Upon receiving the USMC selected Trijicon ACOG Kit, I was impressed with the optical & material quality. It was sighted at home on my AR15M4 16" bbl using the down loadable form from Trijicon, then proceeded to the 25 yard plinking range firing two 3...
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63/64 found this helpful
Helpful Positive Review
Perfectly rugged and simple by JM, Verified Owner, March 6, 2024
This RCO model includes the flash hider and mount. Got it with the red chevron, which in my opinion works reasonably well for close shots once you've practiced on it if you don't have access to a mounted red dot. I ended up buying a rear-shifting mou...
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1/1 found this helpful
Helpful Positive Review
Combat proven by Dave, Verified Owner, March 12, 2024
If you’re reading this then you know what’s up. ACOG/RCO: these things are bullet proof, reliable, work just as needed, and have over two decades of combat under their belts. Despite being considered obsolete, everyone still uses and plans on using t...
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1/1 found this helpful
Helpful Positive Review
The tank of optics! by Boombostic, Verified Owner, April 12, 2024
Super clear glass, nye indestructible, definitely a go to for me!
1/1 found this helpful
Helpful Positive Review
Yes, it is worth the money by Ryan, January 19, 2020
This is by far the best sight I've ever owned. I love my eotech but this is just a huge upgrade over it, in my opinion. Buy it, you wont regret it. Worth every hour stuck at work to afford it. I couldn't believe how clear and crisp the glass really i...
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4/4 found this helpful
Read All 68 Reviews
Reticle: Illuminated Red TA31RCO-M4CP Chevron Illumination Color: Red Finish: Matte Color: Black Weight: 15.1 ozAdjustment Click Value: 1/2 MOAAdjustment Type: MOA Illumination Type: Fiber Optics , Tritium Included Accessories: TA51 Mount Condition: New

Code: TJ-RS-TA31RCO-M4CP-EE

MPN: TA31RCO-M4CP

UPC: 719307302075

List: $1,857.00Save 23%
$1,439.00

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Product Info for Trijicon TA31RCO-M4 ACOG 4x32 USMC M4 Rifle Scope w/ TA51 Mount &

The Trijicon TA31RCO-M4 ACOG 4x32 USMC M4 Rifle Scope w/ TA51 Mount provides the shooter with quick target acquisition at close combat ranges while providing enhanced target identification and hit probability out to 800 meters utilizing the bullet drop compensator. Trijicon TA31RCO-M4CP ACOG 4x32 Scope with BAC USMC Rifle Optic (RCO) for M4 incorporates dual-illumination technology using a combination of fiber optics and self-luminous tritium. The Trijicon TA31RCO-M4 ACOG 4x32 USMC M4 Tactical Scope includes the Tritium that illuminates the aiming point in total darkness, and the fiber-optic self-adjusts reticle brightness during daylight according to ambient light conditions. This allows the operator to keep both eyes open while engaging targets and maintaining maximum situational awareness. Designed to the exact specifications of the United States Marine Corp, the unique reticle pattern on this rifle scope by Trijicon provides the shooter with quick target acquisition at close ranges while providing enhanced target identification. Trijicon ACOG 4 x 32 Rifle Scopes are internally-adjustable, compact telescopic sights with tritium illuminated reticle patterns for use in low light or at night. Trijicon Rifle Scopes combine traditional, precise distance marksmanship with close-in aiming speed that are designed for use with the M16 family.image

Specifications for Trijicon TA31RCO-M4 ACOG 4x32 USMC M4 Rifle Scope w/ TA51 Mount &:

Manufacturer: Trijicon
Objective Lens Diameter: 32 mm
Magnification: 4 x
Reticle: Illuminated Red TA31RCO-M4CP Chevron
Exit Pupil: 8 mm
Illumination Color: Red
Finish: Matte
Field of View, Linear: 36.8 ft at 100 yds
Field of View, Angle: 7 degrees
Eye Relief: 1.5 in
Color: Black
Weight: 15.1 oz
Adjustment Click Value: 1/2 MOA
Length: 5.8 in
Adjustment Type: MOA
Illumination Type: Fiber Optics, Tritium
Fabric/Material: Forged Aluminum
Shockproof: Yes
Fogproof: Yes
Package Type: Polymer Hard Case
Included Accessories: TA51 Mount
Magnification Type: Fixed
Condition: New
Housing/Frame Material: Forged Aluminum
Country of Origin: USA

Features of Trijicon TA31RCO-M4 ACOG 4x32 USMC M4 Rifle Scope w/ TA51 Mount &:

  • Always On, Always Ready: Most ACOG models are battery-free, featuring a tritium/fiber optic illuminated reticle that automatically adjusts the brightness based on available light.
  • Take Control: Several ACOG models are designed with a user-adjustable brightness setting powered by a single AA battery. The 3.5x35 LED and 4x32 LED models both offer six adjustable brightness settings.
  • Rugged, Reliable Housing Design: Fixed-power design allows for minimal moving parts to create a nearly indestructible sighting system.
  • "Both Eyes Open" Design: "Both eyes open" shooting using Trijicon's Bindon Aiming Concept (BAC) feature allows for improved situational awareness.
  • Outstanding Clarity: The quality of the glass and multi-coated lenses maximize light-gathering capabilities and clear field of view with zero distortion.
  • Exact Target Distances & Holds: Most ACOG models feature a bullet drop compensating and target-ranging reticle for decisive aiming.
  • Combat Proven: No other magnified optic has been used more in combat than the ACOG.
  • Shock-Resistant: Proven to withstand recoil from a .22LR to a .50BMG and everything in between. Easily passes U.S. Military drop test requirements.
  • Waterproof: Exceptional waterproof performance that exceeds military standards. Dry nitrogen-filled to eliminate fogging. This optic is tested to withstand and perform in extreme cold and heat with dry-nitrogen filled housing that mitigates fogging.

Package Contents:

  • Trijicon TA31RCO-M4 ACOG 4x32 USMC M4 Rifle Scope w/ TA51 Mount &
  • 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

Trijicon TA31RCO-M4 ACOG 4x32 USMC M4 Rifle Scope w/ TA51 Mount & Orderable Models

List of Orderable Models

  • Trijicon ACOG 4x32 USMC Rifle Scope, For M4, TA51 Mount M4CP-EE , MPN: TA31RCO-M4CP , UPC: 719307302075 , Code: TJ-RS-TA31RCO-M4CP-EE

Trijicon TA31RCO-M4 ACOG 4x32 USMC M4 Rifle Scope w/ TA51 Mount & Unavailable & Discontinued Models

List of Unorderable Models

  • Trijicon ACOG 4x32 USMC Rifle Scope, For M4, TA51 Mount, FREE Gerber Multi-Plier M4CP-KIT2 , MPN: TJ-RS-TA31RCO-M4-KIT2 , Code: TJ-RS-TA31RCO-M4CP-KIT2
  • Demo, Trijicon ACOG 4x32 USMC Rifle Scope, For M4, TA51 Mount M4CP-EE , MPN: 100230-DEMO , Code: TJ-RS-TA31RCO-M4CP-DEMO
  • Trijicon ACOG 4x32 USMC Rifle Scope, For M4, TA51 Mount with Armasight Gen 2+ Day/Night Vision Clip-On System and FREE Gerber Suspension Multi-Plier , MPN: M4CP-KIT3 , Code: TJ-RS-TA31RCO-M4CP-KIT3
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