The Trijicon Advanced Combat Optical Gunsight (more commonly known as ACOG) is an excellent fixed power sight for the AR15 carbine. I’ve owned a couple of them and both were excellent quality scopes.
They are specifically made for ranges as far as 800 meters with a BDC (Bullet Drop Compensator) that is calibrated for 5.56.
They are amazingly rugged and well built (water proof to 500 feet), but on top of that they are also very effective at improving target acquisition and accuracy.
TA31 4×32 ACOG with LaRue mount
The tritium (a low level radioactive isotope) is self-illuminating and lends itself to better shooting in low light conditions and the fiber optic does an excellent job of collecting ambient light and using it to light up the reticle in the daytime. The ACOG does not require batteries. Obvious upsides to this are that you do not have to switch the optic “on” and batteries will never die or need to be replaced.
The ACOG utilizes the Bindon Aiming Concept (or BAC). The BAC allows the user to keep both eyes open when using the sight and helps tremendously in target acquisition.
The ACOG’s design fits well with the BAC due to the bright red “dot” (Obviously this concept works well with other optics with red dots). Most people who are accustomed to shooting firearms with crosshair sights might find this concept strange and unnatural but when they try it with a red dot sight, they usually find out fairly quickly how effective and useful it can be.
Obviously keeping both eyes open gives you some precious peripheral vision, but the greatest benefit overall is the extremely fast target acquisition. Try it on a moving target and you will quickly see how effective this can be.
To learn more about the BAC, go here.
The ACOG is seeing a lot of action in the military operations in Iraq and Afghanistan with great success, specifically the TA31 and TA01NSN models which the US military is purchasing and issuing to as many troops as possible. Many troops who are in units where there are none or too few to go around are buying their own personal ACOG’s.
The US Marine Corp is aiming to field 53,000 scopes by 2010.
Many troops prefer it over an optic without magnification simply because it helps them to identify friend or foe at greater distances.
AR15 Carbine with TA31 ACOG
M4A1 Carbine with TA01NSN ACOG
I have owned two models. The first was a TA31 ACOG with a red donut reticle. The second was a TA50-2, which is a smaller “compact” 3×24 ACOG with an amber triangle reticle.
I eventually decided that the compact ACOG was just a little too small so I sold it not too long afterwards. However, I wish I had kept it longer as I think that I may have grown to like and appreciate it better.
There is no doubt that the ACOG gives the user a huge advantage for combat shooting outdoors and at longer ranges. Having used it in carbine courses I could easily notice the quicker target acquisition and accuracy it helped me achieve in those situations.
However, it’s greatest flaw that I found was it’s ineffectiveness at close ranges, specifically indoors. For my personal use (home defense) and preference, I really want something that can be used indoors primarily and outdoors secondarily.
Therefore I have sold my TA31 as well.
That said, I may go back to it eventually. As I write this, I feel somewhat guilty over it.
Editor’s Note: Since the writing of this blog, I have indeed bought another TA31. No other optic can match what the ACOG does for the AR-15, in my opinion.