Trijicon TA31RMR ACOG 4×32 Scope Review

A great way to discover which product has the most to offer is to head straight towards the most expensive offering. The Trijicon TA31RMR ACOG 4×32 scope certainly has a high price tag, but there are some good reasons why.

This scope is essentially a battle-tested piece of military equipment that has been altered slightly to suit the public market. It has been built using only the most premium materials along with being packed with the latest in technology.

And I’ve been lucky enough to check out exactly what’s on offer from possibly one of the best scopes ever made.

So, let’s find out what I think of it in my in-depth Trijicon TA31RMR ACOG 4×32 Scope Review.

trijicon ta31rmr acog 4x32 scope guide

About Trijicon

Since being founded in 1981, Trijicon has been an industry leader in the development of any light aiming systems. They are proud to be a supplier for the U.S. Marine Corps as well as partnering with government, state, and local law enforcement agencies for decades.

Using this knowledge and experience, the team at Trijicon are also excited to create innovative shooting systems for private use. These products include industry-leading rifle scopes, red dot sights, electro-optics, and iron sights for shooting and hunting enthusiasts.

trijicon ta31rmr acog 4x32

Proud to be American…

The vast majority of Trijicon products are designed, engineered, machined, and assembled in the U.S.A. There are two main facilities located in Wixom, Michigan, and Auburn, California, and are proud to be 100% American.

The Acupoint range of rifle scopes are assembled in the U.S.A but have significant components purchased in Japan. To maintain transparency, all products are clearly marked according to their origin and are backed by a limited lifetime warranty.

Changing the entire industry…

By dissecting a pair of binoculars on a workbench in the garage, the goal was to create a more compact rifle scope using the same prism technology. By 1987 the Trijicon TA01 4×32 Advanced Combat Optical Gunsight (ACOG) was born.

The scope was almost immediately included in the U.S. Army Advanced Combat Rifle program. This is what began what would be a life-changing partnership with the U.S. Military that still continues to this day.

Overall Design

There is a term that is often used yet is even more often greatly exaggerated. That is saying something is “built like a tank.” Well, on this occasion, I can safely say, and possibly even be understating, that the Trijicon ACOG is certainly built like a tank.

When you pick it up in your hand, you can immediately tell that this thing is high quality. The weight alone being 17-ounces (481-grams) gives a great indication that this scope is meant for business with a fit and finish that will easily stand up to years of repeated abuse.

Double the fun…

Easily the most unique part of this scope is the inclusion of a red dot sight mounted on top of the scope. This allows for accurate close-to-mid-range targeting and really means that you are receiving two high-end optics in one.

The combo setup is designed to be compatible with rifles featuring Picatinny rail types. It is possible to remove the RMR (Ruggedized Miniature Reflex Sight), making minor modifications possible if something more advanced ever becomes available.

RMR Dual Illuminated Red Dot Sight

The red dot optic features dual illumination for battery-free operation. This is achieved using fiber optics and tritium to illuminate the reticle. Fiber optics collect ambient light that can automatically adjust brightness according to the conditions.

When faced with low to no light environments the reticle relies on tritium for illumination. This means that no matter what type of situation is being faced, your red dot optic will always be available and ready to operate.

Outstanding red dot features…

Engineered to divert forces away from the lens during an impact, this is one of the most durable red dot optics available. When identifying targets through the lens, it has a true-color multi-coating for wide-band light transmission reducing target area color changes.

trijicon ta31rmr acog 4x32 scope

The optic is waterproof up to a depth of 66-feet (20-meters) for use in all types of weather conditions. It is also simple to adjust both elevation and windage with no special tools required. One click equals 0.5 MOA.

The Main 4×32 Scope

Just like the RMR red dot, the main scope also features the same dual illumination technology. With a fixed magnification power of 4x, this allows for minimal moving parts, creating an almost indestructible design.

The scope has been proven to withstand the recoil from a .22LR up to a .50BMG, along with everything in between. Being the optic of choice for the U.S. Military proves that it can perform in even the toughest of situations.

Class-leading clarity…

Only the highest quality glass has been selected and used in the construction of Trijicon ACOG scopes. They then receive a multi-coating that increases light gathering capabilities, reduces glare, and protects the lens from dirt, dust, oils, and scratches.

Field of view is perfectly clear, with absolutely zero distortion throughout the entire viewing area. Linear FOV is 36.8-feet at 100-yards with a FOV angle of 7-degrees. This helps to provide the fastest target acquisition currently possible.

Incredible accuracy…

A both eyes open design using Trijicon’s BAC (Bindon Aiming Concept) feature provides the ultimate in combat readiness. Users can remain alert with complete situational awareness while still maintaining clear and accurate targeting.

Even over longer distances, Trijicon features a bullet drop compensating and target-ranging reticle. Compensation up to 875-yards (800-meters) can be made without the need to make any manual adjustments.

Ready for all environments…

The scope’s waterproof standards exceed all military standards, so there are no issues with being fully submerged in water. Even pouring rain is no match with the scope continuing to operate at its full capacity.

Dry nitrogen has also been used to fill the scope to eliminate fogging. No matter what the environment throws at you, from dry heat to cold fog, and even snow, you’ll always be ready to line up a shot.


Both the scope and RMR are constructed with a military-grade forged aluminum alloy housing. They are finished in a matte-black color to protect the optics from the elements as well as not giving away your position by reducing any chances of reflections.

It is a compact optic system that measures 5.8-inches (14.73-centimeters) in length. It weighs almost double other comparable compact optics though at 17-ounces (482-grams). This only adds to its durability, though.

Superior lenses…

The objective lens measures 32-millimeters in diameter with 1.5-inches (38-millimeters) of eye relief. There is a fixed magnification power of 4x for the scope and 1x for the RMR red dot sight. Unlimited eye relief is provided by the RMR also.

trijicon ta31rmr acog 4x32 scope reviews

Adjustment type is MOA, with each click equaling 0.5 MOA. The reticle is a TA31RMO4 crosshair that is illuminated in red. There are no batteries required with illumination provided by fiber optics or tritium.


This optic is capable of performing effectively for almost any task. It’s just as competent at consistently providing tight groups on a target as it is for hunting or even tactical warfare. Other than long-range sniper use, this is what gun-owners dream about.

Between the two optic options, you can accurately and consistently hit targets up to about 500-yards (546-meters) away. It is little wonder why this is the optic of choice for both military and law enforcement agencies.

Basically indestructible…

In Iraq, a Trijicon ACOG took an AK round and saved a marine’s life. Not only did it stop the bullet, but the optic continued operating afterward. This should give you a true indication of how durable and reliable these products are. They’re basically indestructible.

The sight picture through both the RMR and ACOG are crisp and bright and truly have to be seen to be believed. The way these optics utilize all the available light is absolutely incredible for both the lens and providing illumination for the reticle.

Trijicon TA31RMR ACOG 4×32 Scope Pros & Cons


  • Optics of choice for U.S. Military and law enforcement agencies.
  • Easily the toughest and almost indestructible optic currently available.
  • Combines RMR red dot and ACOG scope for close to medium-range targeting.
  • Battery-free dual illumination using fiber optics and tritium.
  • Class-leading high-quality glass lenses for superior levels of clarity.
  • Consistently remains accurate with bullet drop compensating reticle.


  • Being possibly the best optic currently available makes it very expensive.
  • Not suitable for long-range targeting over approximately 600-yards (548-meters).
  • No night vision compatibility available at the moment.
  • Limited to 4x magnification power which might fall short for some.

Looking for a New Scope?

Then you’ll enjoy our reviews of the Best Long Range Rifle Scopes, the Best Long Range Scopes under 1000 Dollars, the Best Deer Hunting Scopes, the Best Mil Dot Scopes, as well as the Best AR10 Scopes on the market in 2023.

Or how about our reviews of the Best 300 Win Mag Scopes, the Best Sniper Scopes, the Best 308 Rifles Scopes, the Best Rimfire Scopes, the Best Scout Scopes, or the Best Rimfire Scopes currently on the market.


There is nothing too fancy about this combination of optics. Instead, Trijicon has ensured that it performs every function to the highest possible standard. From the amazing clarity of the glass used for the lenses to the strong and durable aluminum alloy in the housing.

The result is an optic that provides accurate and reliable performance time after time in almost any type of condition. If this is the choice for military and law enforcement professionals, then it will undoubtedly be more than sufficient for private use.

Happy and safe shooting.

5/5 - (72 votes)
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About Wayne Fletcher

Wayne is a 58 year old, very happily married father of two, now living in Northern California. He served our country for over ten years as a Mission Support Team Chief and weapons specialist in the Air Force. Starting off in the Lackland AFB, Texas boot camp, he progressed up the ranks until completing his final advanced technical training in Altus AFB, Oklahoma.

He has traveled extensively around the world, both with the Air Force and for pleasure.

Wayne was awarded the Air Force Commendation Medal, First Oak Leaf Cluster (second award), for his role during Project Urgent Fury, the rescue mission in Grenada. He has also been awarded Master Aviator Wings, the Armed Forces Expeditionary Medal, and the Combat Crew Badge.

He loves writing and telling his stories, and not only about firearms, but he also writes for a number of travel websites.

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