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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 USMC Trijicon ACOG TA31RCO-M4CP Kit by Legacy Reviewer, February 20, 2010
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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59/60 found this helpful
Helpful Positive Review To quote Hodge Defense, IYKYK by Gibby, Verified Owner, October 27, 2022
It's an ACOG. Whether you're a recently served veteran or an enthusiast or a target shooter, the ACOG just works. From Trijicon box to my BCM RECCE 14.5, I zeroed the rifle in 5 minutes with the 25/300BZO. Yes, the eye relief is short. If you are pro...
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2/2 found this helpful
Helpful Positive Review Trijicon ACOG by Chris Valdez, December 4, 2023
So the reason I went with the Trijicon Acog is because that’s what I use while I served in the Marines and I found it to be very accurate. Very easy to use and it’s very durable, now I don’t plan on using it for what I did in the military but if thin...
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1/1 found this helpful
Helpful Positive Review Favorite optic out there by Kris, Verified Owner, March 22, 2017
As a former infantry Marine, I am quite familiar with this optic. The cost is steep but in my opinion, in the end, it is worth it. I have a handful of the other popular optics (EoTech) but, this is my favorite and the one I am most comfortable with. ...
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4/4 found this helpful
Helpful Positive Review Best Combat Optic by AJ, February 25, 2019
I used this in Afghanistan as in Infantryman when my life depended it on it. It can take some serious abuse. The one thing i did notice is that Trijicon has continuously updated the acog. It now illuminates down to the 600 meter stadia, a much needed...
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7/7 found this helpful
Helpful Positive Review Acog is worth its price by Forgetful Coupon User, Verified Owner, January 9, 2020
My purchase was offered free two day shipping but somehow I didn’t apply it during checkout I contacted Optics Planet and within a day a refund was initiated for the cost of shipping! Enjoy your new loyal customer! Now to the optic. Nothing much is n...
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3/3 found this helpful
Read All 65 Reviews
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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: 100230

UPC: 719307302075

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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: Tritium, Fiber Optics
Fabric/Material: Forged Aluminum
Shockproof: Yes
Fogproof: Yes
Package Type: Polymer hard case
Included Accessories: TA51 Mount
Magnification Type: Fixed
Condition: New
Country of Origin: USA
Attachment/Mount Type: Flattop

Features of Trijicon TA31RCO-M4CP ACOG 4x32 Scope with BAC USMC Rifle Optic(RCO) for M4:

  • Military-Grade Aluminum Alloy Housing Forged 7075-T6 aircraft aluminum alloy housing provides for a nearly indestructible sighting system
  • Longer Eye-Relief Maximum eye-relief for larger caliber rifles and large exit pupil for faster target acquisition
  • Internally Adjustable Since only the prism housing moves, the ACOG is much more rugged than the conventional designs
  • Trijicon Fiber Optics Automatically adjusts the brightest level and contrast of the reticle to available light conditions
  • Trijicon Tritium Phosphor Lamp Aiming reticle glows in low-light conditions for quick target acquisition. Lamp is guaranteed to illuminate up to 15 years.
  • Totally Battery-Free ACOG delivers increased hit potential in all lighting conditions - without the use of failure-prone batteries
  • Broad Band Anti-Reflective Coated Lenses Multi-coated lenses provide superior clarity and light gathering capabilities with zero distortion
  • Lifetime Warranty

Package Contents:

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

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: 100230 , 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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