The 3 Best ACOG Sight For AR-15 [2020 Update]

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In this guide I’m going to show you the best ACOG sight for AR-15.

In fact:

These are the same sights that many optic experts and competitive shooters use.

The best part?

I’ve sorted the sights by use. So whether you’re on a budget or need a solid ar15 acog, you’ll find it here.

Let’s get started!

The 3 Best ACOG Sight For AR-15

If you’re pressed on time, here’s a quick list of the best ACOG sight for AR-15:

  1. Trijicon ACOG 5.5 X 50: Best Overall
  2. Trijicon ACOG 3.5×35: Best Trijicon ACOG for AR15
  3. Trijicon 4×32 ACOG: Best ACOG for 3 Gun

1. Trijicon ACOG 5.5 X 50: Best Overall

The Trijicon ACOG has the best features out of all the other ACOG scopes I’ve seen.

In fact:

I had to buy and test it myself to see if it lived up to its claims, and it most certainly did.

Need proof? Keep reading to see more.

Glass Clarity and Reticle

The glass quality is top notch, and easily gives a distortion free crystal clear picture to see through.

Being fully multi-coated, the glass excels at drawing in ambient light so that the image is always crisp and bright.

One of the best parts about the illuminated reticle is the fact that there are no batteries to fail in a critical moment. It’s guaranteed to stay illuminated for up to 15 years, so only in the distant future will you have to worry about it.

The illuminated reticle also auto adjusts depending on the amount of available light. I never had to manually adjust, and the brightness was always exactly what I needed no matter the environmental light.

The reticle itself is solid, and was made to both compensate for bullet drop and to help with rapid target acquisition.

Eye Relief and Eye Box

The eye relief is 2.2”, which is more than enough for an ACOG scope.

As I expected after buying the Trijicon ACOG, eye fatigue wasn’t an issue even after hours of use. The glass is way too clear and there’s no distortion to strain my vision.

The eye box was a non issue, and centering my picture came easily.

The Trijicon ACOG was designed around the Bindon Aiming Concept (BAC), which means it’s meant to aim with both eyes open. This improved my situational awareness incredibly, and rapidly switching targets was easier than it’s ever been.


The Trijicon ACOG is one of the most durable scopes I’ve ever handled.

Even after being dropped, banged around, and even fully submerged in water, this scope still came out on the other side completely unscathed. Despite the intense abuse and testing, it still held my zero afterwards with no issue.

How was it able to handle all of this?

This scope has a fixed-power design, so there are very few moving parts that can be damaged from any sort of trauma. It’s also made with a military-grade aluminum housing, so even cosmetically damaging this scope would be difficult.

It’s also completely waterproof, with no issues operating even in extreme temperatures. It’s nitrogen purged, so there’s no chance of any fogging or moisture getting inside.

Elevation and Windage Knobs

The low turrets on the Trijicon ACOG gave crisp, audible clicks whenever I made adjustments.

They aren’t capped, but are firm and I didn’t run into any issues with them being accidentally knocked out of place.

The best part?

It was incredibly easy to find my zero. It only took 10 rounds, and it held it for the next 200.

Parallax and Magnification

The parallax is fixed, and being a scope with a set magnification this caused no issues that I could find.

The magnification is set at 5.5x.

This scope is essentially a type of ar15 ACOG scope, so long range shots aren’t its strong suit. There are far better hunting scopes out there, and I would recommend using this for combat or target shooting.

Normally close range also wouldn’t be the optimal range for the Trijicon ACOG, but it’s actually viable when using the Bindon Aiming Concept. This versatility and effectiveness at multiple ranges despite having a set magnification is a huge plus for this scope.

Mounting and Rings

The Trijicon ACOG is a bit on the expensive side, but it does come with its own mount.

The TA51 is the flattop mount that comes attached to the scope. This is convenient to where you don’t need to buy one separately, but could potentially limit what you mount this scope on.

Is the Trijicon ACOG 5.5 X 50 worth it?

If you’re looking for an ACOG scope that stands head and shoulders above the rest, then look no further than the Trijicon ACOG.

Here’s why:

  • Extreme durability
  • Crystal clear glass
  • Seamless BAC integration
  • Long lasting illuminated reticle

To sum it up: other ACOG scopes just tend to fall short when compared to the plethora of features that the Trijicon ACOG has at its disposal.

The price is incredibly reasonable for everything that the scope offers. The glass is top notch and the durability is hard to match even looking at different types of scopes.

It may take some getting used to shooting with the BAC style, but not many other scopes allow that type of style and it really pays off with this one. It was built around it and its features all complement this form of shooting.

So if you need an amazing ACOG scope that is versatile and considerably better than its competition, then look no further than the Trijicon ACOG 5.5 X 50.

Trijicon TA55A ACOG 5.5 X 50 Red Chevron BAC Flattop .308 Reticle
  • ACOG 5.5x50 Red Chevron BAC Flattop.308 Reticle includes flat top adapter
  • The chevron reticle is designed to be zeroed using the tip at 100 meters The width of the chevron at the base is 5.53 MOA which is 19 in. at 300 meters This allows range estimation for silhouette...
  • Includes 1 Flattop Mount (TA51) 1 5.5x50 Scopecoat (TA65) 1 5.5x50 ACOG Pouch 1 Lenspen (LENSPEN) 1 Trijicon Logo Sticker (PR15) 1 Manual 1 Warranty Card

2. Trijicon ACOG 3.5×35: Best Trijicon ACOG for AR15

The Trijicon ACOG is the perfect choice for your AR-15

Not only does an ACOG give you the perfect balance between a red dot scope and a LPVO, but with the Trijicon brand you’ll also get a high quality scope.

I was hesitant to spend the money on an ACOG, but once I tried the Trijicon ACOG, I’ve been more than happy that I did.

Want to know why? Keep reading…

Glass Clarity & Reticle

The glass on the Trijicon ACOG is crystal clear.

In fact, I was surprised to find that the glass quality was superb in almost any light condition.

The reason for that is the reticle has a tritium/fiber optic illumination. This automatically adjusts the brightness for you, based on the ambient light surrounding you. The tritium works to illuminate your reticle at night and the fiber optics work during the day.

The best part is that you don’t even need a battery, so you’ll never have to worry about losing your illumination in the middle of a hunt, day or night.

The reticle itself is a red chevron ranging reticle. It’s made specifically for 5.56 rifles and it allows for bullet drop compensation out to about 875 yards! Plus, the red chevron is very easy to see in the daylight or at night thanks to the tritium/fiber optic illumination.

The chevron pulls your eye to the center of target, so you can acquire your target fast. It’s not quite as quick as it would be with a red dot, but it’s pretty close. And it’s definitely a lot faster target acquisition than you’d get with an LPVO. Hence why it’s a great compromise between the two types of scopes.

Eye Relief & Eye Box

Eye relief is pretty low with any ACOG and the Tritium ACOG 3.5×35 is no exception.

Fortunately, I found that this one has the most eye relief out of any other ACOG I’ve seen. Even better than the 4x that Trijicon offers. And with the longer eye relief, you can mount this a little further out from yourself and still get an accurate sight picture.

Plus, you can purchase the Trijicon eyepiece that makes the eyecup much more comfortable pushed up against your face and gives you just a little extra eye relief.

Trijicon ACOG Scope Model Rubber Eyepiece
  • Package length: 13.004 cm
  • Package width: 7.62 cm
  • Package height: 5.588 cm

The eyebox is also one of the biggest of any other ACOG and is perfect for the AR-15.

On top of that, the Trijicon ACOG uses the Bindon Aiming Concept, so you use this scope with both eyes open. This gives you a much better field of view and allows you to use more of your peripheral vision.

Not only is that a huge advantage when it comes to close quarters combat, it also makes target acquisition much faster. That, along with the red chevron reticle, makes it easy to get on target, which is important when your life’s on the line. And it’s great when you’re trying to make a quick shot on fast moving prey.


What I like most about the Trijicon ACOG 3.5×35 is that it is a rugged, nearly indestructible scope.

It is made of aircraft quality aluminum that is almost impossible to dent or damage. I’ve dropped mine a few times and whacked it against a tree and there’s not a scratch on it.

It’s also dry nitrogen filled, which means it won’t fog up and it’s waterproof up to 100 feet. I’ve never dunked mine under water, but I have taken it out in the rain a few times and it still performs perfectly.

Plus, Trijicon offers a limited lifetime warranty, so if you have any problems, they’ll help you get it functioning properly again.

Elevation & Windage Knobs

The elevation and windage knobs are easy to adjust.

The turrets use a tactical MOA adjustment with a maximum MOA of 40 for both elevation and windage.

They are about a ⅓ MOA per click and because only the prism housing moves, which is an internal adjustment, it’s much more rugged and durable than a conventional design.

Zeroing on this scope is the same process as any other and I found it to be quick and easy. In fact, after only a few minutes, I had such tight groups at 100 yards that I could cover them with a nickel!

I’m hard on my scopes and this Trijicon ACOG 3.5×35 has taken a beating and seen a lot of use. It is still holding zero and I’ve never had to readjust it.

Parallax & Magnification

The magnification on this scope is fixed at 3.5x.

At first I thought I’d go for the 4x, but chose the 3.5x because of the longer eye relief. I have to say that the 0.5x difference is pretty negligible and I’m happy with my choice.

It’s pretty manageable at shorter ranges of 30-50 yards, which I’d typically need a lower power to shoot accurately.

And, at distances of 200-300 yards, I can still make very accurate shots. The sweet spot is somewhere in between at about 100-150 yards. At that range, I can shoot holes through holes. For me, that’s the perfect distance for the type of hunting that I mainly do.

Another bonus that makes the Trijicon the best ACOG for the AR-15 is that it is almost completely parallax free. That is if you’re using it right and have a good cheek weld. If you’re not, you could get a slight amount of parallax from side to side. Vertical parallax is non-existent.

Mounting & Rings

You also get a lot of bonuses when you purchase the Trijicon ACOG 3.5×35, including a flat top adapter for mounting it to your AR-15.

You’ll also get a scopecoat, a large Pelican case, a lenspen, and a logo sticker, along with the manual and warranty card.

If you’re a prevalent hunter, you may want to get this Trijicon killflash to reduce glare and keep from giving away your position.


Is the Trijicon ACOG 3.5×35 worth it?

The Trijicon ACOG is top of the line and well worth the cost.

It features:

  • Rugged durability
  • Red chevron reticle
  • Superb glass clarity
  • Day and night visibility
  • Fast target acquisition
  • Battery free illumination
  • Short-medium range accuracy

If you’re looking for the very best ACOG for your AR-15, try the Trijicon ACOG 3.5×35. You’ll be happy you did.

Trijicon ACOG 3.5x35 Riflescopes
  • ACOG 3.5x35 scope with Green Horseshoe BAC Reticle and Target Reference System is calibrated for 5.56 (.223 cal) flat-top rifles to 1000 meters Includes flat top adapter
  • Daytime illumination is provided by fiber optics
  • With TA51 Mount

3. Trijicon 4×32 ACOG: Best ACOG for 3 Gun

The Trijicon 4×32 ACOG is hands down the best ACOG for 3 gun competition shooting.

In fact:

I’m making this crazy claim because this scope provides the highest levels of clarity, color accuracy, and resolution out of the many rifle scopes I’ve tested.

Want to know how? Keep reading, starting with…

Glass Clarity & Reticle

The Trijicon 4×32 ACOG has the best glass quality in the game.

The lenses are fully multi-layer coated for reduced glare and color distortion so you get a bright, accurate sight picture.

The quality of the glass and multi-coated lenses maximize light-gathering capabilities and enable a clear field of view with zero distortion.

The optics are ultra-clear with unbelievable light-gathering thanks to the dual fiber optic and tritium illumination.

The tritium gives a bright, crisp illumination at night, and should last for at least 12 years before needing to be refreshed. At that point, Trijicon will accept the optic to replace the tritium for you.

This means that the reticle is illuminated in low-light, no-light, and daylight conditions- all without batteries. No more searching for the power button, it’s ready to go at the drop of a hat.

The ACOG comes with two reticle options: a .223 Chevron reticle or .223 Crosshair reticle. They come with your choice of red or green illumination and both drop out to 600 yards.

I opted for the .223 BAC Red Crosshair- I personally find that red illumination is easier to see, allowing for faster target acquisition.

Without any manual adjustments, this ranging reticle allows for bullet drop compensation out to 600 meters.

That accuracy combined with the unparalleled glass quality is why I pin it as the best ACOG for 3 gun.

Eye Relief & Eye Box

With only 1.5 inches of eye relief, it’s pretty close, but it’s easy to get used to.

Despite the 1.5 inches of eye relief, the scope design does allow for both eyes open shooting. With a little practice, you can go from nose to the charging handle or a few inches back with the stock fully extended.


The Trijicon ACOG is a grade-A, American made unit.

If you’re looking at the brands made in China, a percentage of them tend to have quality control issues despite costing a large chunk of change.

While the Trijicon is more expensive, it’s a safer investment because they’re made and tested in America to MIL-STD-810G methods and procedures.

In fact:

No other magnified optic has been used more in combat than the ACOG.

This scope is durable- proven to withstand recoil on anything from a .22LR to a .50BMG. You can bet that it passed the U.S. Military drop test requirements.

The fixed-power design means less moving parts and, paired with the 7075-T6 aircraft aluminum alloy housing, translates into a nearly indestructible optic.

It’s water-resistant as well as nitrogen-filled, meaning that you won’t have to worry about the scope fogging. Extreme heat, cold, wet, or dry, you’ll be shooting.

Overall scope weight is another factor to consider, especially when using an ACOG scope for an AR15.

This Trijicon weighs in at 15.1 oz with the stock mount- it’s not the lightest optic. However, investing in an aftermarket lightweight mount can shed some of that weight.

Elevation & Windage Knobs

The new Trijicon 4×32 ACOGs come with hand-adjustable turrets that are very tactile and sturdy.

Both turrets come with aluminum caps on cable lanyards so you don’t have to worry about dropping your lens caps in the field.

They’re O-ring sealed to maintain waterproofing.

It holds a tight zero and has tactile knobs which made zeroing easy.

Parallax & Magnification

The Trijicon ACOG is a fixed 4x magnification with a 32mm objective lens.

Shooting out to 400 yards with this 4x scope is super easy, especially with the crystal clear glass.

With the fixed magnification, the ACOG’s field of view is over 36 feet at 100 yards. Which is unheard of for a scope of this size and weight.

A 3 gun optic needs to perform at close-, mid-, and long-range distances.

While the magnification is fixed at 4x, the glass clarity alone trumps any limitations a normal fixed 4x optic would experience.

I have a number of sub-$500 1-6x scopes, and this ACOG gives me a better target ID at any range just because the glass clarity is phenomenal.

Mounting & Rings

The scope does come stock with its own mount- a TA51 thumb screw mount. There are a ton of aftermarket mounting options though.

Mounting with the TA51 was a breeze, but for the speed of 3 gun competition, I’d recommend a QD mount like the Trijicon AC12028 Short Quick Release Mount.

The mount can be removed exposing a rail on the scope body that can be slid into a carry handle. There’s a hole through this railing allowing you to co-witness with your sights as well.

Is the Trijicon 4×32 ACOG worth it?

Finding the right scope for 3 gun shooting competitions is paramount to your success.

If you’re looking for a rugged and fast-action optic that’s worth every penny, get the Trijicon 4×32 ACOG.

Why? It’s got:

  • 4x magnification
  • Crystal clear glass
  • Military tested durability
  • Tritium and fiber-optic illumination

The impeccable glass clarity alone is one of the reasons why I keep coming back to this particular scope for all of my 3 gun needs.

If you’re considering the Trijicon 4×32 ACOG, you won’t be disappointed.

Now It’s Your Turn

I hope you enjoyed my best ACOG sight for AR-15 guide.

Now I want to turn it over to you:

Which sight will you pick for your AR-15?

Let me know by leaving a quick comment down below.

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