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Questions & Answers
I've got a FSB; do I need a mount to clear the scope over it? Expert Answer

You will need a riser mount for the Trijicon ACOG 4x32mm Rifle Scopes w/TA51 Mount to clear am FSB. The mount at the link below should work.
https://www.opticsplanet.com/american-defense-manufacturing-ad-b3-c-cantilever-acog-base.html

by Hunter, Gear Expert, October 17, 2023
Can you mount a small red dot on top of it? Expert Answer

Yes, you would be able to purchase and install the Trijicon RMR Mount for ACOG Scopes with bosses (linked below) to this Trijicon ACOG TA31, and it would allow you to mount an optic that uses the Trijicon RMR optic footprint.
https://www.opticsplanet.com/trijicon-rmr-mount-for-acog-scopes-with-bosses.html

by Ethan, Gear Expert, August 11, 2022
Customer Reviews
Helpful Positive Review
I purchased this scope for my new Scar 16s NRCH. As this is a battle tested scope, I was eager to test it out. I was extremely pleased with the eyes wide open experience. Extremely clear optic with red crosshairs, designed for the 223 rifle. I sight...
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17/23 found this helpful
Helpful Positive Review
ACOG TA31 M193 by Jerry, October 24, 2022
I emailed Trijicon about a scope for a AR with 16" barrel. They answered and said the model M193 was for 5.56mm AR"s' with 16" barrels. They are correct. It work's great. I like it. Works well in low light. Light weight. Needs lense covers.
3/3 found this helpful
Helpful Positive Review
worth every penny by Sneadoh, January 1, 2023
After coming back to civilian life full time, I thought I’d give every optic I could find a turn to see how they’d run. Everything within the price point of an ACOG fell short at something and certain things excelled! Tango 6T’s glass or Burris’s win...
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9/9 found this helpful
Helpful Positive Review
Best AR optic IMHO by DoItAll, Verified Owner, March 29, 2023
Dating back to my time in service, I will say that IMHO, the ACOG TA31 4x32mm rifle scope is the best optic for an AR for anything close quarters to 300 yards. I've tried a half dozen sights from major players in the optics world with military contra...
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7/7 found this helpful
Helpful Positive Review
Amazing scope by JR, Verified Owner, April 2, 2023
Love it! Fantastic, fast scope. My favorite for all purpose plinking with my AR Great up close too and works like a red dot to me. I have it on a LaRue LT100 mount which is awesome. For all around shooting and say hog hunting this is a great sco...
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1/1 found this helpful
Helpful Positive Review
Have ACOG, Will Travel by Yo Payly, February 15, 2024
I've used these in every environment we could that has destroyed everything else. Minus 30º to 120º in the shade. Salt water, sand storms, jungles, and mountains. Fell out of aircraft, bounced around in offroad vehicles, and limousines in cities. I...
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5/5 found this helpful
Read All 28 Reviews
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Product Info for Trijicon ACOG 4x32mm Rifle Scopes w/TA51 Mount

The Trijicon 4x32mm ACOG Rifle Scope robust engineering and enhanced user control. The electronics on this Rifle Scope from Trijicon offers an outstanding level of reliability with a straightforward brightness dial, allowing the operator to determine how much to illuminate the reticle-even in transitional lighting. The body on the Trijicon ACOG 4x32mm Illuminated Weapon Scope, has been optimized by moving the RMR mount forward to maximize its performance in conjunction with the ACOG. This Trijicon Gun Sight is fully compatible with night vision devices.image

Originally paired with the TA51 mount, this Trijicon ACOG TA31 4x32 Rifle Scope stands out for its exceptional performance. The patented ACOG reticle adds a layer of user-friendly innovation – adjusting the reticle subtensions is a breeze. Manipulate them with your mouse, choose the desired range, and the red dot remains constant. Should you opt for manual reticle rotation, it's at your fingertips. Once you've fine-tuned the reticle to your specifications, a quick rotation and release of tension secure your adjustments. The reticle seamlessly resyncs automatically when exposed to any light source, ensuring uninterrupted functionality. Elevate your shooting experience with the Trijicon ACOG TA31 4x32mm Rifle Scope – where precision meets innovation. Choose the Trijicon Advanced Combat Optical Gunsight - 4x32mm for a great way to improve your accuracy.

Specifications for Trijicon ACOG 4x32mm Rifle Scopes w/TA51 Mount:

Manufacturer: Trijicon
Objective Lens Diameter: 32 mm
Magnification: 4 x
Tube Diameter: 32 mm
Exit Pupil: 8 mm
Finish: Matte
Field of View, Linear: 36.8 ft at 100 yds
Field of View, Angle: 7 - 7 degrees
Eye Relief: 1.5 in
Weight: 15.1 oz
Length: 5.8 in
Adjustment Type: MOA
Parallax: Fixed
Illumination Type: Fiber Optics/Tritium
Fabric/Material: 7075-T6 Aluminum
Lens Material: Glass
Optical Coating: Multi-Coated
Brightness Settings: 6
Water Resistance Level: Waterproof
Shockproof: Yes
Fogproof: Yes
Package Type: Polymer Hard Case
Magnification Type: Fixed
Additional Features: ACOG TA31
Condition: New
Country of Origin: USA
Attachment Type: TA51

Features of Trijicon ACOG 4x32mm Rifle Scopes 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 ACOG 4x32mm Rifle Scopes w/TA51 Mount
  • Thumbscrew Flattop Adapter (TA51)
  • 4x32 Scopecoat (TA63)
  • LENSPEN (TA56)
  • Lanyard Assembly for Adjuster Caps (TA71E)
  • Trijicon Logo Sticker (PR15)
  • ACOG BAC Manual
  • Warranty Card

Trijicon ACOG 4x32mm Rifle Scopes w/TA51 Mount Orderable Models

List of Orderable Models

  • Trijicon ACOG TA31 4x32mm Rifle Scope, Sniper Gray, Illum Red Chevron .223 / 5.56x45mm Reticle, MOA Adjustment, 100308 , MPN: TA31-D-100308 , UPC: 719307307223 , Code: TJ-RS-ATA31-100308
  • Trijicon ACOG TA31 4x32mm Rifle Scope, Flat Dark Earth, Illum Green Chevron .223 / 5.56x45mm Reticle, MOA Adjustment, 100313 , MPN: TA31-D-100313 , UPC: 719307307278 , Code: TJ-RS-ATA31-100313
  • Trijicon ACOG TA31 4x32mm Rifle Scope, Flat Dark Earth, Green Crosshair .223 / 5.56x45mm Reticle, MOA Adjustment, 100380 , MPN: TA31-C-100380 , UPC: 719307307971 , Code: TJ-RS-ATA31-100380
  • Trijicon ACOG TA31 4x32mm Rifle Scope, Black, Red Chevron .223 / 5.56x45mm Reticle, MOA Adjustment, TA31F , MPN: TA31F , UPC: 719307300095 , Code: TJ-RS-ATA31-TA31F
  • Trijicon ACOG TA31 4x32mm Rifle Scope, Black, Red Chevron 5.56x45mm M193 / 55 Grain Reticle, MOA Adjustment, 100288 , MPN: TA31-D-100288 , UPC: 719307306882 , Code: TJ-RS-ATA31-100288
  • Trijicon ACOG TA31 4x32mm Rifle Scope, Flat Dark Earth, Illum Red Chevron .223 / 5.56x45mm Reticle, MOA Adjustment, 100310 , MPN: TA31-D-100310 , UPC: 719307307247 , Code: TJ-RS-ATA31-100310
  • Trijicon ACOG TA31 4x32mm Rifle Scope, Black, Green Chevron 5.56x45mm M193 / 55 Grain Reticle, MOA Adjustment, 100290 , MPN: TA31-D-100290 , UPC: 719307306868 , Code: TJ-RS-ATA31-100290
  • Trijicon ACOG TA31 4x32mm Rifle Scope, Flat Dark Earth, Illum Green Horseshoe/Dot .223 / 5.56x45mm Reticle, MOA Adjustment, 100367 , MPN: TA31-D-100367 , UPC: 719307307780 , Code: TJ-RS-ATA31-100367
  • Trijicon ACOG TA31 4x32mm Rifle Scope, Sniper Gray, Illum Green Horseshoe/Dot .223 / 5.56x45mm Reticle, MOA Adjustment, 100365 , MPN: TA31-D-100365 , UPC: 719307307766 , Code: TJ-RS-ATA31-100365
  • Trijicon ACOG TA31 4x32mm Rifle Scope, Sniper Gray, Red Crosshair .223 / 5.56x45mm Reticle, MOA Adjustment, 100370 , MPN: TA31-C-100370 , UPC: 719307307889 , Code: TJ-RS-ATA31-100370
  • Trijicon ACOG TA31 4x32mm Rifle Scope, OD Green, Illum Green Horseshoe/Dot .223 / 5.56x45mm Reticle, MOA Adjustment, 100366 , MPN: TA31-D-100366 , UPC: 719307307773 , Code: TJ-RS-ATA31-100366
  • Trijicon ACOG TA31 4x32mm Rifle Scope, OD Green, Illum Green Chevron .223 / 5.56x45mm Reticle, MOA Adjustment, 100312 , MPN: TA31-D-100312 , UPC: 719307307261 , Code: TJ-RS-ATA31-100312
  • Trijicon ACOG TA31 4x32mm Rifle Scope, Black, Amber Chevron .223 / 5.56x45mm Reticle, MOA Adjustment, 100216 , MPN: TA31F-A , UPC: 719307301313 , Code: TJ-RS-ATA31-TA31F-A
  • Trijicon ACOG TA31 4x32mm Rifle Scope, OD Green, Green Crosshair .223 / 5.56x45mm Reticle, MOA Adjustment, 100379 , MPN: TA31-C-100379 , UPC: 719307307964 , Code: TJ-RS-ATA31-100379
  • Trijicon ACOG TA31 4x32mm Rifle Scope, OD Green, Illum Red Chevron .223 / 5.56x45mm Reticle, MOA Adjustment, 100309 , MPN: TA31-D-100309 , UPC: 719307307230 , Code: TJ-RS-ATA31-100309
  • Trijicon ACOG TA31 4x32mm Rifle Scope, Flat Dark Earth, Red Crosshair .223 / 5.56x45mm Reticle, MOA Adjustment, 100372 , MPN: TA31-C-100372 , UPC: 719307307902 , Code: TJ-RS-ATA31-100372
  • Trijicon ACOG TA31 4x32mm Rifle Scope, Sniper Gray, Green Crosshair .223 / 5.56x45mm Reticle, MOA Adjustment, 100378 , MPN: TA31-C-100378 , UPC: 719307307957 , Code: TJ-RS-ATA31-100378
  • Trijicon ACOG TA31 4x32mm Rifle Scope, Sniper Gray, Illum Green Chevron .223 / 5.56x45mm Reticle, MOA Adjustment, 100311 , MPN: TA31-D-100311 , UPC: 719307307254 , Code: TJ-RS-ATA31-100311

Trijicon ACOG 4x32mm Rifle Scopes w/TA51 Mount Unavailable & Discontinued Models

List of Unorderable Models

  • DEMO, Trijicon ACOG TA31 4x32mm Rifle Scope, Black, Green Chevron 5.56x45mm M193 / 55 Grain Reticle, MOA Adjustment, 100290-DEMO , MPN: 100290-DEMO , Code: TJ-RS-ATA31-100290-DEMO
  • DEMO, Trijicon ACOG TA31 4x32mm Rifle Scope, Black, Red Chevron 5.56x45mm M193 / 55 Grain Reticle, MOA Adjustment, 100288-DEMO , MPN: 100288-DEMO , Code: TJ-RS-ATA31-100288-DEMO
  • OPEN BOX, DEALER DEMO, Trijicon ACOG TA31 4x32mm Rifle Scope, OD Green, Red Crosshair .223 / 5.56x45mm Reticle, MOA Adjustment, 100371-DMO , MPN: TA31-C-100371-DMO , Code: TJ-RS-ATA31-TA31-C-100371-DMO
  • DEMO, Trijicon ACOG TA31 4x32mm Rifle Scope, Black, Red Chevron 5.56x45mm M193 / 55 Grain Reticle, MOA Adjustment, TA31F-DEMO , MPN: TA31F-DEMO , Code: TJ-RS-ATA31-TA31F-DEMO
  • DEMO, Trijicon ACOG TA31 4x32mm Rifle Scope, Black, Amber Chevron .223 / 5.56x45mm Reticle, MOA Adjustment, 100216 , MPN: 100216-DEMO , Code: TJ-RS-ATA31-TA31F-A-DEMO
  • DEMO, Trijicon ACOG TA31 4x32mm Rifle Scope, Flat Dark Earth, Illum Green Horseshoe/Dot .223 / 5.56x45mm Reticle, MOA Adjustment, 100367 , MPN: 100367-DEMO , Code: TJ-RS-ATA31-100367-DEMO
  • OPEN BOX, DEALER DEMO, Trijicon ACOG TA31 4x32mm Rifle Scope, Flat Dark Earth, Green Crosshair .223 / 5.56x45mm Reticle, MOA Adjustment, 100380-DMO , MPN: TA31-C-100380-DMO , Code: TJ-RS-ATA31-TA31-C-100380-DMO
  • DEMO, Trijicon ACOG TA31 4x32mm Rifle Scope, Flat Dark Earth, Green Crosshair .223 / 5.56x45mm Reticle, MOA Adjustment, 100380 , MPN: 100380-DEMO , Code: TJ-RS-ATA31-100380-DEMO
  • DEMO, Trijicon ACOG TA31 4x32mm Rifle Scope, Flat Dark Earth, Illum Red Chevron .223 / 5.56x45mm Reticle, MOA Adjustment, 100310 , MPN: 100310-DEMO , Code: TJ-RS-ATA31-100310-DEMO
  • DEMO, Trijicon ACOG TA31 4x32mm Rifle Scope, Flat Dark Earth, Red Crosshair .223 / 5.56x45mm Reticle, MOA Adjustment, 100372 , MPN: 100372-DEMO , Code: TJ-RS-ATA31-100372-DEMO
  • DEMO, Trijicon ACOG TA31 4x32mm Rifle Scope, OD Green, Green Crosshair .223 / 5.56x45mm Reticle, MOA Adjustment, 100379 , MPN: 100379-DEMO , Code: TJ-RS-ATA31-100379-DEMO
  • DEMO, Trijicon ACOG TA31 4x32mm Rifle Scope, OD Green, Illum Red Chevron .223 / 5.56x45mm Reticle, MOA Adjustment, 100309 , MPN: 100309-DEMO , Code: TJ-RS-ATA31-100309-DEMO
  • Trijicon ACOG TA31 4x32mm Rifle Scope, Black, Amber Chevron 5.56x45mm M193 / 55 Grain Reticle, MOA Adjustment, 100289 , MPN: 100289 , UPC: 719307306875 , Code: TJ-RS-ATA31-100289
  • OPEN BOX, DEALER DEMO, Trijicon ACOG TA31 4x32mm Rifle Scope, Sniper Gray, Green Crosshair .223 / 5.56x45mm Reticle, MOA Adjustment, 100378-DMO , MPN: TA31-C-100378-DMO , Code: TJ-RS-ATA31-TA31-C-100378-DMO
  • DEMO, Trijicon ACOG TA31 4x32mm Rifle Scope, OD Green, Red Crosshair .223 / 5.56x45mm Reticle, MOA Adjustment, 100371 , MPN: 100371-DEMO , Code: TJ-RS-ATA31-100371-DEMO
  • DEMO, Trijicon ACOG TA31 4x32mm Rifle Scope, Sniper Gray, Green Crosshair .223 / 5.56x45mm Reticle, MOA Adjustment, 100378 , MPN: 100378-DEMO , Code: TJ-RS-ATA31-100378-DEMO
  • DEMO, Trijicon ACOG TA31 4x32mm Rifle Scope, Sniper Gray, Red Crosshair .223 / 5.56x45mm Reticle, MOA Adjustment, 100370 , MPN: 100370-DEMO , Code: TJ-RS-ATA31-100370-DEMO
  • DEMO, Trijicon ACOG TA31 4x32mm Rifle Scope, OD Green, Illum Green Horseshoe/Dot .223 / 5.56x45mm Reticle, MOA Adjustment, 100366 , MPN: TA31-D-100366-DEMO , Code: TJ-RS-ATA31-100366-DEMO
  • Trijicon ACOG TA31 4x32mm Rifle Scope, OD Green, Red Crosshair .223 / 5.56x45mm Reticle, MOA Adjustment, 100371 , MPN: 100371 , UPC: 719307307896 , Code: TJ-RS-ATA31-100371
  • DEMO, Trijicon Limited Edition ACOG Three Color Tiger Camouflage 4x32mm Rifle Scopes w/TA51 Mount, Dual Illuminated Red Chevron Reticle, Three Color Tiger Camouflage, 100763 , MPN: 100763-DEMO , Code: TJ-RS-ATA31-100763-DEMO
  • Trijicon Limited Edition ACOG Three Color Tiger Camouflage 4x32mm Rifle Scopes w/TA51 Mount, Dual Illuminated Red Chevron Reticle, Three Color Tiger Camouflage, 100763 , MPN: 100763 , UPC: 719307619340 , Code: TJ-RS-ATA31-100763
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