Down in the comments of this post, commenter Kevin mentioned ACOGs. That naturally raises the question, “What’s an ACOG?”

ACOG is the acronym for Advanced Combat Optical Gunsight. Trijicon, Inc. has made a line of specialty gunsights for the M-16/M-4 family of weapons for years now. And last year, after using a variety of different products from different manufacturers, the Army settled on the ACOG as the primary sight for the M-4.

Back in the Stone Age, when I was a grunt, all small arms, with the exception of sniper weapons, only had “iron sights.” They were fairly accurate, but took quite a bit of training to master. Further, they were very difficult to use in low light, such as early in the morning and late in the evening. They were of course, next to useless at night.

Iron sights on the M16A2
Iron sights on the M16A2

Traditionally, the Army (and to a lesser extent, the Marines) have been leery of adopting optical gunsights, mostly because of their perceived fragility. The other big factor was that they cost money. Now, in an era when a jet can cost more than the GDP of many small countries, you’d think a few hundred bucks for a scope would not matter. But that’s not how the defense budget works. When the Army only has a limited amount of money to buy stuff, they tend to focus on the big ticket items. Small stuff, like small arms and their accessories, tends to get pushed aside.

One of the consequences of the Army going into Afghanistan and Iraq was that there was a sudden push to make sure our troops had what they really needed in terms of all their gear. That freed up a lot of money for things that otherwise just weren’t going to be bought. Grunts have been watching police and recreational shooters use combat optics on their rifles for nearly 30 years. Not surprisingly, there was a big push to update the Army with combat optics.

Now, a rifle scope is actually not what you really want in most firefights. A scope actually narrows your vision and can even make it harder to see the target. But combat optics use what are called “reflex sights” that are meant to be used with both eyes open. This greatly aids in target acquisition and generally keeping up ones situational awareness.

The first big batch of combat optics was the M68 Close Combat Optic, or CCO. Unlike the crosshairs of a traditional scope, the reticle of a CCO is illuminated, making it easier to see, and far more instinctive to use. There was just a simple red dot. Put the dot on the bad guy, pull the trigger, make the bad guy go away. The CCO didn’t even magnify. It just made it easier and faster to aim. About the only drawback to the CCO is that it takes batteries to illuminate the “death dot”, and grunts already have enough to carry, without having to worry about carrying extra batteries.


Next up, and recently standardized is the M150 RCO (Rifle Combat Optic). This is the Army name for Trijicon’s Advanced Combat Optic Gunsight. The ACOG works along pretty much the same lines as the CCO, but provides some magnification (either 3.5X or 4X) and doesn’t need batteries. It uses radioactive tritium to provide the illumination for the reticle.

ACOG, or M150 RCO
ACOG, or M150 RCO

Variations of the CCO and the ACOG are also mounted on the M249 SAW and the M240 medium machine gun.

6 thoughts on “ACOG”

  1. Sorry to go off topic, xbrad, however, I was wondering what you knew about the new rules of engagement for soldiers in Afghanistan? When did they take effect? Who’s orders? Why? Is it from the White House specifically (as opposed to a push from Gates).

  2. Nice post xbrad.
    The ACOG sounds like righteous optics, especially the no batteries part. I’m glad to hear our guys in the field will be getting better equipment, and am sure that it’ll be handy in Afghanistan…

    All the best

  3. Mare, the revised ROE are from McChrystal. They mostly apply to using air support and artillery on structures. Does it have the risk of costing American lives? Yes. But when you are trying to win the support of the population, it’s important to not blow them up. Or even flatten their house. That doesn’t mean that you can never blow up a house with terrorists in it. It just means that it isn’t option A.

  4. I’ve long “back-of-the-mind wondered about the close-in fire-fight “head out” situational awareness aspect of the thing, but from what you’ve provided here and from what little I’ve seen on You Tube, the troops seem to take to it pretty well. Not your Grand-fathers’ M1 and iron sights for sure.

    One thing however. In Af the distances are so great, I would think the M-16 would have trouble with striking/penetrating power compared to the M-14, etc. Is it the problem I think it could be? I know in the Falklands campaign the Brits complained that across the longer ranges on the island tundra their automatic wpns lacked the “reach” and punch that their rifles had, and they wished they had had more of the latter for that campaign. Is same true in Af?

  5. Virg,

    A quick glance at FM22.3.9 (Rifle Marksmanship, M16/M4 Series)shows the M16 and M4 are fairly well matched at ranges up to about 300m. No one is going to claim the 5.56mm is a great round for long range shooting.

    The M855 round from an M16A2 will penetrate a steel helmet at 1000m. But neither it nor the M80 7.62mmX51 NATO round will penetrate a sandbag at 100m.

    And don’t forget, most of the enemy is armed with AK series in 7.62mmX39. Any problems we have at longer ranges are even greater for them. The AK is very dangerous at 100m. And while it can kill at ranges much greater than that, it isn’t what one would call a powerhouse round.

    Indeed, while the argument over the 5.56mm round will go on indefinitely, there’s no real argument that the 5.56mm is a better round the longer the range, when compared to the 7.62mmX39.

    One of the ways the Army and Marines (and other nations) have addressed the issue is using the Designated Marksman.

    See here:

    And here:

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