The ACOG scope has been a staple of military and law enforcement for decades. With the introduction of the TA02, Trijicon brings the ACOG into the age of battery-powered technology.

The TA02 ACOG builds upon the combat-proven legacy of the TA31 4-power ACOG sight, introducing battery-powered illumination.

In this review, we’ll discuss the performance, build quality, reticle, pros and cons, and who it’s for.

Verdict up Front

The Trijicon TA02 is the ideal ACOG for those who want consistent, reliable illumination, day or night, with all the ruggedness ACOGs are known for.

Battery-powered ACOGs, such as the TA02, address the primary limitation of fiber-optic illuminated ACOGs by offering bright and easily adjustable illumination with the turn of a dial. Gone are the days of your ACOG reticle being too dark or too bright for your shooting situation. Shooting in low light is vastly improved because the TA02 is not reliant upon ambient light for illumination. The 12,000-hour battery life means you can run the scope on a single AA battery for over a year.

If you want a fixed 4x magnification scope that can endure the harshest, most abusive conditions, there is none better than the TA02 ACOG.

✅ Best For: Tactical use, law enforcement, rugged civilian setups

❌ Not Ideal For: Long-range precision, variable zoom needs

ACOG TA02 Quick Specs Table

Feature	Spec
Magnification	4x
Objective Lens	32mm
Reticle	Red or Green LED (multiple options)
Power Source	1x AA Battery
Eye Relief	1.5 in
Weight	18.1 oz
Mounting	Flattop Picatinny rail
Waterproof/Fogproof	Yes (up to 66 ft)

Brief History of the ACOG

The US military first started fielding the Advanced Combat Optical Gunsight (ACOG) back in 1991, shortly before Operation Desert Storm. Previously, rank-and-file infantry soldiers and Marines had used iron sights almost exclusively on their weapons. By 2005, US Special Operations Command had fielded over 12,000 ACOGs, and the US Marine Corps had officially adopted the ACOG as the Rifle Combat Optic (RCO).

The most prevalent ACOG scopes adopted by the US Military are the TA01 and TA31. Both the TA01 and TA31 ACOGS feature fixed 4x magnification. The TA01’s reticle is only illuminated with a tritium vial (the identical tritium used in pistol night sights). In contrast, the newer TA31 utilizes tritium, along with a fiber optic rod on top of the optic, to provide additional illumination of the reticle. The tritium illumination on ACOGs is very dim and only useful in extremely low-light situations.

Hundreds of thousands of ACOG sights have seen combat with the US military at this point. While the US Marine Corps is phasing out the fixed-power 4x ACOG, the optic remains in use by multiple branches of the military and will continue to serve for years to come.

TA02 Versus the TA31 ACOGs

I will frequently reference the TA 31 ACOG scopes throughout this review. The TA31 is the ACOG with which most are familiar. It’s the ACOG most commonly seen on US military rifles.

The TA02 is a battery-powered version of the TA31. Both the TA02 and TA31 are 4×32 fixed magnification. The forged housing is slightly different on the TA02 to accommodate the battery and electronics. Both scopes share the same mount, glass, and reticles. The TA02 weighs 4 oz more than the TA31.

Design & Build Quality

The TA02 ACOG is built using the same forged and anodized aluminum housing as all ACOGs. The robust forged construction affords the TA02 extreme durability. The optic is fully waterproof, shock-proof, and fog-proof.

The battery compartment is on the lower right side of the optic. The battery cap is O-ring sealed for waterproofing, and it is conveniently captive, ensuring you won’t lose it.

Windage and elevation knobs are in familiar places on the top and side of the optic. No tools are required to adjust the scope’s point of impact. The elevation and windage caps are also captive using a thin wire, which is a nice feature for an optic designed for the average infantry Marine.

Optic Clarity & Field of View

ACOGs use very high-quality, German-made Schott glass in their construction. Schott glass is among the highest-quality glass found in any scope. The image is crystal clear, with no distortion anywhere in the field of view.

One of the significant benefits of 4×32 ACOGs, such as the TA02, is the vast field of view. The field of view on the TA02 is 36.8 feet wide at 100 yards. The wide field of view makes observation and targeting extremely easy. Scopes with narrow fields of view sometimes feel like you’re looking through a straw; this is not the case with the TA02.

Another benefit of 4×32 ACOG sights is low-light performance. Due to the 32mm wide objective lens, the scope gathers light incredibly well. Shooting in dusk or dawn lighting is a non-issue. The LED-illuminated reticle shines (no pun intended) in these situations. The brightness adjustment lets you dial in the perfect amount of illumination for any shooting condition. Adjustable illumination is what I love most about the TA02.

Reticle Options

The TA02 ACOG currently comes in three main reticle options. All ACOG reticles are available in red or green illumination. There are multiple reticles with ballistic drop compensators (BDC) calibrated for .556, .308, and 300 BLK.

In each reticle picture you’ll notice hash marks for various distances. Provided the BDC aligns closely with your weapon and ammunition, it makes accurate shooting at distance relatively simple.

For range estimation, you can use the width of each hash mark. The width of the hash mark is the approximate width of a man’s shoulders at a given distance (19 inches). You can use these hash marks to estimate the distance to the target and the appropriate hold for the given distance.

Crosshair: Provides the most precise aiming point with the finest crosshair intersection of the available reticles.

Chevron: The most common reticle issued to the US Military. Designed for quick target acquisition while still offering precision.

Horseshoe Dot: Designed for speed with less emphasis on precision.

Illumination

All TA02 ACOG scope reticles are available in red or green illumination. Green is supposed to be more easily visible to the human eye, but it provides less contrast in very green environments. Red offers the best contrast in a wide range of environments. I’ve used both and don’t have a strong preference either way, but I buy ACOGs with red illumination because I like the high contrast. If you’re undecided about which color to choose, opt for red.

On-demand brightness adjustment on the TA02 ACOG is one of its best selling points. The brightness adjustment knob on the TA02 has six brightness settings. There is an off setting between each brightness setting, so you only need to turn the knob one click from your preferred brightness to turn it off. I like this feature, so it’s quick and easy to turn the optic on and have it at your preferred setting.

Brightness setting 1 is the dimmest setting. It works well in low light or when you want a more precise aiming point. Setting one is very similar to the brightness created by the tritium on the TA31. If you’ve used a TA31 or other tritium ACOG, you’ve got a good idea of what I’m referring to.

I usually run my illumination around settings 3 or 4, depending on the situation. At these settings, the reticle remains crisp and precise while being highly visible. Settings 3 and 4 remain sufficiently bright when shooting at night with a weapon light.

Setting six is exceptionally bright. Similar to a TA31 in broad daylight with the fiber optic completely exposed to the sun. At setting 6, the reticle starts to bloom because it’s so bright. Precision is degraded with the illumination so bright, but you won’t have any trouble seeing the reticle. I’ve never been in a situation where I needed to run the brightness on setting 6.

Real-World Shooting Experience

The TA02 ACOG is best suited for short to mid-range shooting. 4x magnification is low enough that shooting fast at 25 yards is doable but not ideal. It’s slower than a red dot at 50 yards and in. Mounted to an AR-15, 100-500 yards is the TA02’s bread and butter. Target identification and engagement is very fast compared to many scopes. The magnification is perfect for hitting a full-size IPSC target out to 4-500 yards. Making hits on an 8 inch steel plate at 2-300 yards is trivial.

The BDC on the ACOG reticle makes it relatively easy to judge distance and make quick and accurate hits at extended ranges. Simply use the hash marks to estimate distance and pull the trigger. It’s that easy.

The ranging feature works surprisingly well in practice. Even a relatively inexperienced shooter can learn to use it quickly and get effective hits at extended ranges.

How to Zero the TA02 ACOG

Zeroing the ACOG sight is critical to making the most of the BDC. With a proper zero, the BDC hash marks will line up with your rifle’s point of impact making ranging and longer range shooting relatively simple.

The standard zero for a rifle where the BDC matches the weapon is 100 meters. On the crosshair reticle you zero using the first crosshair. For the chevron reticle you zero using the pointy tip of the chevron. And on the Horseshoe reticle you zero using the center dot located inside the horseshoe.

If you’re using an ACOG not specifically calibrated to your exact rifle and ammunition, it’s best to break out a ballistic calculator to determine the best zero for your given rifle and ammunition. For example, I zero one of my TA02 ACOGs at 120 yards because that allows the ranging hashmarks to most closely match my rifle’s and ammunition’s ballistics. Your ammunition and rifle setup will be unique so it may require a unique zero to optimize the ACOG’s BDC.

Eye Relief

One of the biggest complaints about the TA02 and all 4×32 ACOG scopes is the eye relief. The eye relief is relatively short at 1.5″. I can understand why some people dislike it. It takes some practice to ensure you keep a consistent cheek weld and eye relief when aiming the rifle.

While the short eye relief of the TA02 is a downside, it’s one of the trade-offs we must accept to achieve a relatively small scope with such a massive field of view. It doesn’t take much practice to get used to keeping your eye in the eye box to maintain a good sight picture. On my personal TA02, I use an offset mount, which moves the scope back about an inch. This makes a huge difference for me.

The short eye relief can be mitigated with practice, offset mounts, and adjustable stocks. The benefits of the TA02 4×32 ACOG outweigh this con for me.

ACOG TA02 vs Other ACOGs

If you’re shopping for an ACOG, consider a few other versions as well. Each has its pros and cons. The 3.5x magnification TA11 and the 3x magnification TA33 can fulfill similar roles to the TA02. I prefer the wide field of view and LED illumination of the TA02. There is also a battery-powered version of the TA11 called the TA110. The TA11 and TA110 are much larger than the TA31/TA02 though.

Model	Pros	Cons
Trijicon ACOG TA02 (4×32, Battery-Powered LED)	✅ LED reticle with user-adjustable brightness ✅ Consistent performance in all lighting ✅ Night vision compatible ✅ Rugged 7075-T6 housing ✅ Uses standard AA battery ✅ No reliance on ambient light	❌ Short eye relief (1.5″) ❌ Heavier than fiber optic models ❌ More moving parts (battery compartment)
Trijicon ACOG TA11 (3.5×35, Fiber Optic + Tritium)	✅ Excellent eye relief (2.4″) ✅ Bright, Fiber-optic Illumination ✅ Great field of view ✅ Lighter than TA02 ✅ No batteries required	❌ Bulkier footprint ❌ Reticle brightness tied to ambient light ❌ No user control over illumination ❌ Narrower field of view
Trijicon ACOG TA33 (3×30, Compact Lightweight Option)	✅ Lightweight and compact ✅ Long eye relief (2″) ✅ Ideal for lightweight builds ✅ Fiber/tritium illumination (no batteries) ✅ Faster target acquisition than 4x	❌ Narrower field of view ❌ Slightly less magnification (3x) ❌ Small objective lens = darker image in low light

Mounts

The stock mount included on the TA02 and most ACOGs is the Trijicon TA51 picatinny mount.

The TA51 mount is outdated, but it gets the job done. The mount attaches to any Picatinny rail using two Colt knobs. Similar to how a detachable AR-15 carry handle sight attaches.

The mount is relatively heavy compared to some aftermarket options, and it does not feature quick-detach capabilities.

If the mount is not installed correctly, it can loosen over time. When mounting the TA02 to a rifle, be sure to tighten the knobs hand-tight. Then, use a screwdriver to tighten the knobs an additional half turn. I’ve never had an ACOG come loose using this method during my military and civilian time, despite using ACOGs extensively.

ACOG Upgrades

The TA02 ACOG in its stock form is an outstanding scope. It doesn’t require any upgrades to be a reliable workhorse of an optic. With that said, the biggest weakness is the mount. One of my issued ACOG sights came with a Larue quick-detach mount, which was excellent. I’ve also used an American Defense quick-detach ACOG mount, which was also a significant upgrade over the stock TA51 mount.

Another upgrade I make to my ACOGs is adding a kill flash (also known as an anti-reflective device). The kill flash reduces glare to the shooter in bright sunlight and prevents light from reflecting off the scope’s objective lens. If minimizing your signature is important to you, it’s a cheap but critical component.

The last upgrade I did to my TA02 was adding a top-mounted RMR red dot sight. The RMR takes the ACOG from a mid-range powerhouse and gives you red dot speed at close quarters. With the RMR, I achieve red dot speed at close range, while the 4x magnification of the TA02 covers the mid-range. The RMR red dot also serves as a backup sight, so in the unlikely event that my ACOG fails, I have another sighting option.

Conclusion

I’ve spent a lot of time using ACOG scopes. My issued M16 and M4 were equipped with the TA31. I carried that thing on training exercises and deployments through some truly heinous conditions. I watched a rifle thrown from a moving truck onto the pavement, and the ACOG survived. When it was time for me to buy my own magnified optic for my AR15, there was no question in my mind that I’d be buying an ACOG.

The TA02 version of the ACOG alleviated my biggest gripe by offering immediate and precise brightness control with no dependence on ambient light or tritium. Yes, the TA02 requires an AA battery, but the battery life is so long that it’s a non-issue for me. And since AA batteries are so standard, getting more is cheap and easy. If the battery died and I had no replacements, the TA02’s etched reticle still works exceptionally well as long as you’re not shooting in pitch darkness.

The TA02 builds upon the best aspects of the ACOG and addresses its shortcomings. Making the TA02 the best ACOG variant on the market.

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