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Questions & Answers
Does this optic have the white markings on the left hand side that denote the aimpoint of the reticle at each yard line? Expert Answer

The reticle may be viewed here:
https://www.trijicon.com/images/product_reticles/TA31-D-100582_reticle_popup1.jpg

Mark H.

by Mark H., Gear Expert, August 9, 2018
Can a RMR be mounted to this scope? Expert Answer

Yes, you can mount an RMR to the Trijicon 4x32 ACOG Scope but you will need this mount here:
https://www.opticsplanet.com/trijicon-rmr-mount-for-3x30-acog.html

by Hunter, Gear Expert, January 24, 2022
Customer Reviews
Helpful Positive Review
Trijicon 4x32 M855 RCO red horseshoe by Adam, Verified Owner, May 3, 2021
Amazing optic. Came clean, clearly new from optics planet. Larue tactical 799 qd mount is awesome. Came with carry case. Manuals. And ajustable wrench. Optic is perfect. The price was a steal for 1200$. Its listed for 1750$ on trijicons website.
9/12 found this helpful
Most Recent Reviews
Trijicon ACOG TA31-D-100582 Horseshoe BAC Reticle by Oh3kusmc, Verified Owner, September 13, 2025
If you missed out on the Primary Arms ACSS retiicle ACOG like I did, the TA31-D-100582 is for you. The reticle on this ACOG is about as close to the ACSS you'll get and it comes from Trijicon. The LaRue Tactical mount is very solid and does not wiggl...
Read More...
Most Recent Reviews
Acogs are as advertised by Keithy baby, Verified Owner, November 16, 2024
My second one. Bought the 3.5x model with the .308 crosshair reticle which is on my piston driven LMT quad 16" rifle and this one is on my LMT 20" quad rifle. Only thing I want better is the eye relief but not a deal wrecker plus I knew that prior to...
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Read All 3 Reviews
Reticle:
Horseshoe/Dot
Illumination Color:
Red
Color:
Black
Adjustment Click Value:
1/2 MOA
Adjustment Type:
MOA
Illumination Type:
Fiber Optics, Tritium
Condition:
New

Code: TJ-RS-ACOGLM-100582

MPN: TA31-D-100582

UPC: 719307312142

List: $1,857.00Save 26%
$1,369.00

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OP Bucks$37.48

made-in-usa-flag Made in USA

Help support American manufacturing! Marked models of this product have gone through rigorous review and been certified by the manufacturer as Made in the USA.

Product Info for Trijicon 4x32 ACOG Scope, Dual Illuminated Red Horseshoe/Dot M855 RCO Reticle w/ LaRue Tactical LT799 Mount

The TA31USN-M855 is an Advanced Combat Optical Gunsight (ACOG) designed for either the M16A4 weapon system (20 barrel) or the M16M4 (14.5 barrel). It incorporates dual illumination technology using a combination of fiber optics and self-luminous tritium. This allows the aiming point to always be illuminated without the use of batteries. The tritium 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.image

The unique reticle pattern provides quick target acquisition at close combat ranges while providing enhanced target identification and hit probability out to 1,000 meters utilizing the Bullet Drop Compensator.

No tools are needed for windage and elevation adjustments because the TA31USN-M855 features external adjusters, making it waterproof up to 11m without the caps.

The TA31RCO-M855 includes:

1 LaRue Tactical Mount (LT799)

2 Assemblies, 1/10 Miliradian External Adjusters

2 External Adjuster Caps

1 Lanyard Assembly for Adjuster Caps (TA71E)

1 Scopecoat (TA96)

1 LENSPEN (TA56)

1 RCO Manual

1 Warranty Card

Specifications for Trijicon 4x32 ACOG Scope, Dual Illuminated Red Horseshoe/Dot M855 RCO Reticle w/ LaRue Tactical LT799 Mount:

Manufacturer: Trijicon
Objective Lens Diameter: 32 mm
Magnification: 4 x
Reticle: Horseshoe/Dot
Exit Pupil: 8 mm
Illumination Color: Red
Field of View, Angle: 7 degrees
Eye Relief: 1.5 in
Color: Black
Adjustment Click Value: 1/2 MOA
Length: 6 in
Adjustment Type: MOA
Illumination Type: Fiber Optics, Tritium
Shockproof: Yes
Fogproof: Yes
Package Type: Polymer Hard Case
Magnification Type: Fixed
Condition: New
Country of Origin: USA

Features of Trijicon 4x32 ACOG Scope, Dual Illuminated Red Horseshoe/Dot M855 RCO Reticle w/ LaRue Tactical LT799 Mount:

  • The Trijicon ACOG (Advanced Combat Optical Gunsight) is a fixed power
  • compact
  • Rifle Scope with an illuminated reticle pattern for use in bright to low/no light
  • The ACOG is
  • designed to be extremely durable and reliable
  • Combining traditional
  • precise distance
  • marksmanship with CQB speed
  • many variants include a bullet drop compensated (BDC)
  • reticle
  • Every feature of its design was chosen for a single purpose: to provide increased
  • hit potential in all lighting conditions.

Package Contents:

  • Trijicon 4x32 ACOG Scope, Dual Illuminated Red Horseshoe/Dot M855 RCO Reticle w/ LaRue Tactical LT799 Mount

Trijicon 4x32 ACOG Scope, Dual Illuminated Red Horseshoe/Dot M855 RCO Reticle w/ LaRue Tactical LT799 Mount Orderable Models

List of Orderable Models

  • Trijicon 4x32 ACOG Scope, Dual Illuminated Red Horseshoe/Dot M855 RCO Reticle w/ LaRue Tactical LT799 Mount, Red, 100582 , MPN: TA31-D-100582 , UPC: 719307312142 , Code: TJ-RS-ACOGLM-100582

Trijicon 4x32 ACOG Scope, Dual Illuminated Red Horseshoe/Dot M855 RCO Reticle w/ LaRue Tactical LT799 Mount Unavailable & Discontinued Models

List of Unorderable Models

  • DEMO, Trijicon 4x32 ACOG Scope, Dual Illuminated Red Horseshoe/Dot M855 RCO Reticle w/ LaRue Tactical LT799 Mount, Red, 100582 , MPN: 100582-DEMO , Code: TJ-RS-ACOGLM-100582-DEMO
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