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As I sit here at my desk examining (read: ogling) the ACOG model TA31RCO-M150CP that Trijicon was kind enough to entrust me with, my first impression is…ruggedness. The kind I was previously unaware existed in rifle optics. While the glass on the scope clearly isn’t up to Zeiss standards (see what I did there?) it’s very bright for such a compact sight. I’d place the brightness on par with a 30mm Leupold Mark V. The field of view at 100 yards is a very generous 36.8 feet which provides a good balance of situational awareness and precision. The scope feels not only idiot- but also soldier- proof. Don’t get me wrong with that statement — soldiers aren’t dumb, but if there’s a surefire way to break something, they’re the ones who will figure it out . . .

The TA31RCO-M150CP’s Bullet Drop compensator is zeroed for the M16a4, the M4, and the SAW. This makes it an attractive package for the military as it means this model ACOG is much more versatile than, say, its Soviet counterpart, the POSP (which is only calibrated for a specific cartridge from a specific barrel length). It’s also great for the average AR-15 enthusiast who may own both 20- and 16-inch rifles and wants to share one optic between them. The fixed 4x magnification also not only gives that “just right” level of magnification for most targets, but its fixed nature also makes the optic less prone to breaking under heavy stress.

Speaking of which, if you’re going to invest in an upper-end optic like an ACOG I can’t emphasize enough how useful and convenient ARMS levers are. (Not pictured) I was spoiled by having them on my EOTECH holosight and didn’t think much of them until I had to make due with thumb screws. At least Trijicon was kind enough to cut a relief slot so that a coin can help you get a little more leverage.

Another aspect of the ACOG is the option it gives the shooter to use of the Bindon Aiming Concept – or aiming with both eyes open. While that’s sometimes doable with traditional magnified optics, with the large illuminated the ACOG has, it seemingly superimposes itself on the target like a holosight. That means better situational awareness when engaging moving or multiple targets. And if you close the ACOG’s forward lens cap, you can utilize the sight like a red dot.

Speaking of that lens cap, if you take a careful look at the front of the ACOG you’ll noticed a hexagonal honeycomb pattern that covers the forward aperture, this is the patented killFLASH anti-reflective system. What it does is diffuse the reflected light or glare coming off the front objective that’s normally a dead giveaway that someone is aiming at you. While a lens hood would function in the same manner, it would require the ACOG to extend an extra 5 inches or so which would defeat the purpose of having such a compact sight.

I mounted the ACOG on my 3 favorite .223 rifles; a BCM AR15a4, a BCM M4a3 Midlength, and a Sig 556 Patrol Carbine. The optic was a breeze to mount and an absolute joy to shoot on all 3 platforms. The bullet drop compensator is accurate within 3 inches on all platforms out to 200 yards. The sight never seemed to lose zero and in fact was close enough when switching platforms (assuming the same ammo used) that unless shooting at 300 yards, it would hardly affect point of impact.

Specifications: Trijicon ACOG TA31RCO-M150CP

Magnification: 4x
Objective Size: 32
Bullet Drop Compensator: Yes
Length (In): 7.3
Weight (oz): 16.2
Illumination Source:  Fiber Optics & Tritium
Reticle Pattern: Chevron w/ Target Reference System
Day Reticle Color: Red
Night Reticle Color:Red
Eye Relief: 1.5
Field of View (Degrees): 7
Field of View @ 100 yards (ft): 36.8
Adjustment @ 100 yards (clicks/in):2
Mount: TA51
Housing Material: Forged Aluminum
MSRP: $1,698.00

Design  * * * * *
In a word, awesome. The sight will likely outlast the user. And his children.

Durability  * * * * *
The ACOG is rubber-coated and overbuilt without being cumbersome. Clearly designed for people who are shot at for a living, it’ll serve a civilian indefinitely.

Usability  * * * * ½
“Point the red arrow at the bad people” is pretty straightforward. Tool-less windage and elevation adjustments make zeroing a breeze.

Value * * * * ½
While quality doesn’t come cheap and there are several fine optics out there in the ACOG’s price range, none of them are as versatile or durable. If throw levers were included, this would have been a five star rating.

Overall * * * * *
Rock-solid design combined with bright, vibrant optics makes the ACOG the paradigm for other scope manufacturers to live up to.

Manufacturer’s website

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  1. Are ACOGs the cat’s behind? Sure. I have a hard time plunking down DOUBLE what my rifle cost, though. Seems Trijicon is just a little too proud of their fixed-magnification scope. JMHO.

      • Ditto. I have a Trijicon TA33-8 (3×30 in amber) that I picked up used for around $600. It’s the most amazing glass I’ve ever used and the BAC (Binden Aiming Concept) is phenomenal. Assuming you do *any* rifle shooting beyond 200yds and are serious about hitting what you aim at, you need glass like this. It changes the whole game…

  2. I was under the impression from various literature that the RCO was calibrated for a 14.5″ barrel. Also, the Eye relief still seems really shirt for a goo tactical optic.

    • If you go to, they say it is calibrated for the 14.5 inch barrel, m885 roundl(about 2900fps). The trijicon website is out of date.


  3. Sorry I have a long memory. When Trijicon started grinding off the words of Christ from their scopes, my dollars went elsewhere. You call yourself a Christian but deny him? Nope not for me…ever. I don’t forget.

        • The reson that Trijicon “ground” the words off of the ACOG’s is that the US military asked them to not put it on there ACOG’s

          this has nothing to do with the ones that you buy….unless you are purchasing a stolen ACOG from someone that stole it from the Military

          Even then the Military was the one to file off the scripture numbers. You can contact Trijicon and ask for an optic without the scripture and they will be happy to ship it to you.

          for those that ask the scripture is all about shedding light on things which is a play on what the optic does through the tritium and fiber optic in the scope not anything about killing folks or jihad.

          No I am not a christian nor am I muslim i’m actually an agnostic so really I don’t care whats on the side of one of the best optics on the market…maybe hello kitty pictures?

        • I’m actually thinking of buying one now that you mention they ground that christian nonsense off, that along with about a 150-200 price drop and I’ll grab one or two.

    • Agreed. I need Bible verses on all my firearms and accessories to infuse them with the Holy Spirit and make me a more effective armchair soldier.

      I also write 2 Corinthians 5:9 on all of my ammo casings. Whether home or away, I aim to please Him!

    • Some of us prefer not to have religious graffiti on our equipment – there is nothing stopping you from engraving whatever you choose on yours, but not as easy for me remove it afterwards. I assume by “grinding off” you meant they simply dont engraveit in the first place – I wouldn’t want my optic “ground on either” hence my preference for a product that excludes the practice in the first place. I will also assume you don’t purchase any equipment that hasn’t been endorsed by Jesus. That must be rough.

    • I don’t Care if it’s signed by Satan himself, if I had the cash for the scope I’d put it on my rifle and enjoy my hedonistic opulence every day at the range.

    • Huh, I was under the impression that the Army had requested Trijicon remove the numbers that reference Bible verses because keeping them there provided a propaganda tool for the Taliban and al-Qaida (Sp?). I was also under the impression that Trijicon told the Army to forget it.

      I guess my information might be out of date. In any case, I dont see it as a big deal. I do not need (nor do I mind having) Bible verses referenced on my optics.

      I dont see how not putting those references on your product is denying Christ. You set a pretty high bar for anyone with aspirations for being a Christian. Nursing a grudge takes a lot of work. Lighten up man.

      • Nursing a grude? It’s not a grudge. Just a simple decision I made. Do business with those who you can trust. When a company goes out of their way to make it known they are a “Christian business”, that is what raises the bar. They were the ones who put the Bible verses on all their products for a decade prior. I expect them to defend their faith. They didn’t. I also wouldn’t do business with a company like H-S Precision that went out of their way to hire the killer of the wife of Randy Weaver. Shot an unarmed woman thru the head while holding her baby. What kind of people would hire a guy like that? Not the kind I want to associate with thank you.

        I am quite sure the world will keep spinning on its axis if I do or don’t business with such folks. But I will be happy I am keeping to my values. You can go about your life as you see fit.

        • Regarding doing business with a company that hired Lon Horiuchi, the FBI sniper that killed Randy Weaver’s wife, I have to agree.

        • I expect them to defend their faith.

          If you want religious indoctrination, go see Billy Graham. If you want a good optic for a gun, see Trijicon. Clearly, you value belief in an imaginary friend over build quality.

        • Old thread. Cant help but respond. The military has required all equipment be sans manufacturers logos, ad phrases, etc., since mid ww2. Reason? To deny the enemy any ability to connect the dots,intel, regarding how much of a certain issue item we had.
          Look at ww2 jeeps, early Ford script jeeps were produced, Willys also. Subquent jeeps had to be delivered without brand.
          I love God with my whole being. I dont need a acog with any verse. I fully understand the need not to give our present enemies anything they can use for propaganda purposes. The script acog did just that, and information we had proved it. Why allow the radicals anything to recruit with?
          There are many cool dustcovers you could put on. I keep mine clean of expressive phrases, I figure some prosecutor would use as proof that I am some sort of zealot, as evidence of some sort of pre meditation. Dont laugh, they do this in court commonly.

        • I would say that the Lord would understand that the folks at Trijicon had to make a choice to keep ACOGs going down range to the guys at the pointy end of the spear. As a fellow who has used an ACOG in combat, and loved it by the way, I appreciate that.

          If I ever venture into the world of the modern black sporting rifle, it will carry an ACOG.

    • I’m for biblical markings on Hellfire, brimstone, lightning, and any anvils He drops. I’d prefer a quote from Sgt. York on small arms. Just IMO.

    • Legend has it, Tommy is still engraving the word of God on his Primary Arms 1x scopes with the ACSS reticle.

  4. How did this post just show up within the last couple hours, but get slotted in between two that are timestamped (based on first comment) between 2 pm and 3:30 pm yesterday? Might want to move this to the front page. I only saw it because Tommy Knocker’s comment was in the “Recent Comments” box.

  5. Overpriced. The optic is not worth all the hype. You can do just as well with Iron sights. I have used knockoffs that were $1500 less and every bit as functional, minus the battery-free low light illumination (same fiber illumination).

    • Yeah, the ACOG overpriced and not worth it. Just like the tools at Harbor Freight & Northern Tool are just as good as Craftsman or Snap-On, and only half the price!

      Although, you did say $1500 less. So… $1700 – $1500 = $200. I’d be interested to see a $200 optic of comparable features, quality and functionality. Would you care to share which one it was?

      • The closest to that statement I have seen is a Burris AR series, and even that will run you out to 500+ and is battery operated, with no choice of reticle.

        • Have you ever actually had an ACOG next to it to compare and contrast? If not, why not sign up an account on our forums (link in my name) and then you can send your clone and I will do a comparison of the two and then send it back to you. You pay for shipping to me, I pay for shipping back to you. Seems fair doesn’t it? You can contact me on the forums (listed on there as Kory)

        • @OODALOOP:

          If the $200 version lasts ten years under my level of use, it is worth it. The half-life of tritium is roughly ten years, so the ACOG would need replacing anyhow. Abracadabra: I just saved myself $1400, which I can then spend on ammo.

        • I have fired an AR with an ACOG. The comparison was about two weeks apart, so not a side by side. There is not $1500 of difference between them.

          Comparing the two is like comparing a PSA AR to a Colt AR. One will break the bank, but both get the job done. Show me someone that swears that a Colt AR is better than all other production ARs and I will show you a brand wh0re. Same goes for the ACOG fanatics. The $1500 you save will buy you at least 2 new ARs, a sweet Leupold/Vortex/Nightforce Scope for your LR rifle, 10 cans of LC 5.56, or many other items to add to your collection. High price =/= value. If you have the money to blow on it, more power to you.

          Honestly, if you are putting glass that is not holographic on a carbine, and does not signifigantly magnify your target for precise shots, you are better off with iron sights. Just my opinion.

        • Rambeast: Since I kinda started this argument with you, I wanted to hop back in. I’ve done some reading over the past few days on these things, generically termed the “$200 chinese knockoff ACOGs” or as some call them “FACOGs.” It seems that the consensus is that for probably 75% of the people out there who simply want a holographic sight with the ACOG look, the $200 knockoffs are plenty good enough. They may not have a feature or two, or they may not be as IED durable as a true ACOG, but how many people are going to bang it off the doorframe of their HUMVEE 3-4 times a day for six months? If your life depends on it, if you require bulletproof reliability, then the ACOG is the way to go. If not, the cheap one is probably “good enough” for most people.

          Honestly, in that way, I guess my Northern Tool vs Snap-On analogy is still accurate. If you need a wrench for occasional use around the house, a couple times a year, go to Northern Tool and pay 60-70% less (if not more! Snap-On tools sting!). But if your life and/or livelihood depend on it, you get the Snap-On.

          I still take issue with the attitude of “overpriced and not worth the hype.” Typically that’s the kind of sour grapes thing you hear from people who can’t afford (or at least can’t justify) to spend that much money on an optic. (I’m not saying that you can’t afford it, but that’s usually the people who are loudest with the “not worth it” type comments.) But those people are also usually buying it for a range toy. They’re not counting on it every day, and betting their lives on it.

  6. While not addressing the breathtaking price of new Trijicons, I’d also suggest looking at the 3X version. The difference in magnification is balanced by the wider FOV and larger exit pupil.

    • Yup. The TA33’s have fast acquisition, are very light (mine is right at 11oz with the QR mount), is smaller than the 4x and is amazing glass. I used to poke fun at folks who “wasted” their money on $$$$ optics, thinking that a comparable optic can be found for 1/5 the price. Yup, thought that right up to the point where I actually got to use a ACOG for an extended period of time. After that, there’s very little comparison.

    • I like the ta31. It actually has a WIDER fov than the ta33.
      as for eye relief, yes, the ta33 has more. So, you can have a cheek rest a bit further back. When I went to basic traing as a grunt, we were taught to put our nose on the rear of the charging handle, mainly to get a bunch of dumb privates to learn the importance of repeating a good cheek weld, important to accuracy. Plus we were using the m16a1, so that makes all the more sense with those iron sights.
      The size of the objective lense on the ta33 is a bit larger than on the 31. That, along with the eye relief, makes it a bit faster to get on target for many. Good for 3 gun i guess. I have never done 3 gun so cannot say. However, if being able to see more of what is going on at distance, like what other bad guys are doing, the 31 is for you. Even for my purposes, i like to have a wider fov.
      Very good responses and post. I always check in here to read what you smart guys have to say. I chuckle at the whining about cost. Let me come to your house and put my price on any used item you will be selling. People who whine about the cost of high quality items have never bothered to study what it costs to manufacture. Between legit costs, land, building, etc., insurance, payroll, etc., then non legit costs, such as the high cost of govt regs, etc….Amazing we havent run every last manufacturer offshore. But we will before it is over.
      If you are a plinker at the local range, go buy a cheap scope you can replace easily when it breaks. The ACOG is not a target scope. It is a combat scope and has saved the life of many an American. It is also a compromise, like all things in life. So, what is your purpose? Determine that first. Stop whining. Go shoot. Smile some, lighten up Francis. And, Merry Christ Mass!

  7. I’ve used 2 Bushnell Trophy 1X R-G dot optics, I think my total cost was $250 for two, i’ve had them for years on many different platforms. Mil Spec? No, but then I will not be playing soldier any time soon. Rugged enough for field use and self defense? You Betcha

  8. I haven’t even had children yet, I hope we live longer than 10 yrs. By that point the Tritium illuminated reticle, one of the major selling points of this $1,800 scope, will be fading.

    • I actually dislike the illuminated reticle already on the Acog. I plan to sell mine on armslist next spring, but i may grab a new one if prices come down. But to your point although not exactly, I dislike the reticle.

  9. I do love the ACOG. My first two deployments I had one on my “work rifle.” The ACOG is darn near impossible to throw off zero. IED? Still zeroed. Climb over the four foot wall…and find out it’s a 12 foot wall from the other side…still zeroed. Whacked off the door jamb of the MRAP too many times to count getting out in a hurry? Still zeroed. Loved it in low light, perfect magnification for urban operations where 250 meters is a long shot.

    My third deployment they gave me an M68. Oh how I disliked the M68. Replaced it with my personal EOTECH. Why you may ask do I have a personal EOTECH? I really, really, really wanted an ACOG for my personal M4 (S&W M&P Carbine). Unfortunately, I just couldn’t justify the cost. I don’t do a lot of urban combat operations around the house. At $1700 the ACOG just didn’t make sense. (Instead I bought the EOTEC, 10 MAGPUL P-MAGs, 4,000 rounds of XM855, and a Glock 30.)

    • I know this is late, a few years, but I just got interested in the M4 platform. Anyways I just picked up a Trijicon ACOG 4×32 Scope w / Red Illumination Doughnut Reticle BAC-M16 / AR15 for just over $800 brand new from OpticsPlanet. It was on sale plus an extra 10% off so bought the sight and mount for $860. I didn’t ask them if they had a Veterans discount, I wasn’t thinking, but if you really want a Trijicon it may not be what you had in the 82nd Airborne Division but it is a good sight.
      Aloha Snackbar!
      God Bless America!

  10. As to battery life; I believe I have replaced one in 4 years and I keep roughly 6 spares handy. I wonder how many hearing aid batteries I could buy for the $1500 differance in price? Mepro’s newer IR units have an average battery life of 8,ooo hrs, that’s 333- 24 hour days of usage YMMV of course

  11. The Trijicon Acog is a great scope system for short to mid range, beyond 400-500 yards/meters, a distance most cannot shoot well at with any scope, the Acog is pretty much useless.
    I have one on my carbine .223 and it works well(30-under 300) but mounted it on my White Oak and Rainer comp uppers and I could shoot tighter groups with my Burris and Vortex then I could with the Acog beyond 525 or so with heavy grain match .223.
    I understand why the military picked this system for the carbines and lower grain 5.56 and similar weapons, very fast accusation of targets out to 200 or so, acceptable to 350 or so, and this is perfect being 99% of all small arms battles in all wars are fought under 300.
    If you plan to be in combat, or are just a range or outdoor shooter who plans to shoot out to 300-400 max, there is nothing that will beat the Acog.
    But for myself and those who wish to test the .223 or similar round out farther up to and in some cases beyond 1,000 but for sure over 500, the Acog is not a good choice. This scope was meant for combat, PERIOD.
    I have a Leupold Mark 4 and a Vortex Razer HD and they destroy the Acog in long-range shooting. I wouldn’t necessarily chose either of those in a combat situation, I’d probably pick the Acog, but for the majority of us not going to war who wish to shoot very well beyond the typical 300-400 most ranges offer, I’m going with a real glass scope and not the Acog.
    Acog is a possible five out of five star scope, no argument there. I think they would double if not triple their sales of Acog’s if they lowered the price to or under 1k, not that raising sales is their main priority. I’ve seen a small drop over the last 4-5 years but for a scope that is not dominant at long ranges accurately it’s a hard sell for someone that wants a long-range scope. For a combat scope YES. But who among us is going to war?

  12. As for the optic, tough to beat Trijicon. No batteries, no switches, no problem. If you prefer an optic system which; is not always ready go, and uses batteries, and has to be activated by a switch, go with an Eotech. If you like the Aimpoint sights, go with them. I really can’t trash the Aimpoint’s because short of running on a battery not much ever goes wrong with them. Having the ability to leave your optic on for literally years without needing to change batteries is an advantage shared by only Aimpoint and Trijicon. It is my opinion the Trijicon gets the edge simply due to the battery issue, but given battery life with the Aimpoints, the difference is slight. As for the $200.00 and under argument, best of luck! Seriously if this is your budget, skimp on the rifle not the optics. You would be better served with a high end optic on a budget ar than the other way around.

  13. Talked to a Marine that came back from Afganistan, they fielded ACOG’s on their M4’s, His statement ” the only siights I would ever have on my weapon are ACOG, or Eotech” Nuff said

  14. After two tours to Afghanistan as a grunt in the 82nd, I believe the Acog is the end all be all of mid range combat optics. No dead batteries, great eye relief and to lose the zero you’d have to be trying.

  15. Necro time: this article doesnt explain whether or not you have to replace the tritium after x amount of years.

    • Tritium has a half life of 12.5 years. Anything with tritium as a component will have to be periodically renewed or replaced. It’s just math.

  16. The comment section was easily the best part of this article. I absolutely love it.. I won’t buy an instrument created for killing people unless it is inscribed with a bible quote. Oh the irony and hypocrisy, gotta love Christianity.

    • That isn’t Christianity talking as anyone with more than a passing knowledge of His teachings knows well.

    • I may be too late on this subject lol but I just wanted to address the comment saying Christians are hypocrites and say that’s invalid. Some people claiming to be christian do give a bad reputation yes. However if you were to truly read the bible you would see it never contradicts itself because God never contradicts His self. the bible says thou shalt not kill correct. However if you look at the actual Hebrew translation it says murder. King David killed many of the wicked men and the bible says david was a man after Gods own heart. Which means you have to be able to discern and not get tricked by the devil like Adam and eve did. That’s why Jesus said be wise like serpents but gentle like doves. Gotta use your brain and understand what God is saying words are much deeper than most people think. It just takes a little searching.

      • Exactly.
        The replacement of the words “commit murder” with “kill” is a recent & duplicitous move by a pacifist clergy.
        The former is indeed the correct historical version.

  17. A lot of hate toward Christ here. Interesting. When I see people freaking out over the mere mention of Christ, it validates his existence to me. Why be so offended by something that isn’t real? Billy Graham once mentioned that the cross and Christ are offensive to people because it confronts them about their behavior. It pricks their consciences. I see that the posts here validate his point. I think some folks here assume that they’re going to live forever. Asinine. It’s equally asinine to say that God isn’t real but it’s okay to say that the universe came from nothing. Life must come from pre-existing life, folks. Get over the hate and evaluate your origins. Give Christ a chance.

  18. I am waiting for my first ACOG to deliver. I am extremely excited. I hope it lives up to the many positive reviews I have found.

  19. you guys are MASSIVE selloust with these auto playing commercials that I cant stop

    last time I visit this site, used to be good and honorable, not any more

  20. Great article. I have a TA33 and I absolutely love it. Yes they are expensive but they are worth it! I think the optic is probably even more important than the rifle you put it on. You can get a rifle that is more accurate than most shooters for well under a $1000 but a great optic is how to leverage that accuracy! Check out my full review of my ACOG including a visual diagram of how to use the bullet drop compensator to estimate a target’s distance:×30-scope-review-f5af914db00b

  21. I’ve owned a trijicon ACOG and some of the other brands. You can’t beat an ACOG. However, there are tons of other brands for $1000 dollars less which get the job done and I would base if off what you’re looking to use it for. If I was in combat, I’d bet my life on an ACOG but if I’m at the range or just hunting, the other brands get the job done for $1000 less. The most recent one I bought was the terminus Optics Scope off of Amazon. Great range piece and I use it for hunting. But like I said, if I was in the heat of combat, I’d for sure go with Trijicon.

  22. As far as occluding (covering the front lense) of my TA-02 ACOG, it caused 4″ point of aim shift to the left and a bit up at 10 feet, so that doesn’t work. As far as accuracy, with all m855, 193, and BTHP 77 gr, it causes horizonal wandering. I believe it has something to do with parallax. Beautiful clarity, but it is the least accurate scope I own. I wish I never bought it. I may put my aimpoint back on, or even a budget optic. Sad
    that I lost $1050 on a poor buy. I don’t call 4″ at 100m acceptable.

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