You're getting a lot of different answers for this, to the point where I'm almost reluctant to tell you another method.
However, the 25m zeroing procedures for the ACOG, whether it's TA01NSN, TA31F, or TA31RCO-M4, basically any ACOG calibrated for a 14.5" barrel, according the Army Small Arms Integration Book, and the method which I have used to zero several ACOGs, including my personally used ACOG, as well as those in my platoon, is to use the 300m aiming point, and place it directly on the center of mass.
Unfortunately, I don't know how to get you the correct graphic aides, I would suggest you or your platoon leader or platoon sergeant go on AKO and look up the SAIB, but imagine if you will, a standard 25m zeroing target. It does not matter whether it's for an M16A1, M16A2, M4, or even an M68 CCO. As long as it has the silhouette on it, the adjustments will have to be done by guesswork and fiddlework, as far as I know, there are no good ACOG zeroing targets that will correctly give you the proper clicks, though instructors have been known to come up with all sorts of strange formulas.
The zeroing target has a silhouette in the center, and the page is divided into quarters, with thick black lines vertically and horizontally through the center. If you extrapolate those lines, they intersect directly on the center of mass of the silhouette. Keep this in mind.
For the TA01NSN, it is simple, just superimpose the reticule's crosshairs over the lines on the target. That will put your 300m aiming point in the center of mass of the target.
For the chevron reticules, the 300m aiming point is actually at the bottom of the chevron, as if you had taken an imaginary line, and drawn it across the bottom lines of the chevron, or the red tip of the BDC stadia. However, for these purposes, it is easier to simply use the chevron legs, and place them on the horizontal lines across the target. Again, your 300m aiming point will now be direct center of mass.
The example in the SAIB is of the M4 zeroing target. Again, it is simply a matter of the proper offset, however, the POI of your group should be 1.3 blocks down from the COM of the silhouette. Remember, this is for the M4 zeroing target. I you use a different zeroing target, make sure you get the proper offset, I don't remember it off the top of my head. I'm simply looking at the SAIB right now.
The offset accounts for the difference in the height over bore of the ACOG versus iron sights. Also, with the chevron, this will allow you to see the ranging reticule in action, as the width of the chevron legs should match the simulated 300m target.
M4 25m Zeroing Target
POA: COM at 300m
POI: COM - 1.3 blocks
It is always good to reconfirm this zero at 100m, or as far out as the situation allows. However, if you zero with these methods, and do it correctly, you will qualify, you will shoot well, and you will not need to you use your Kentucky Windage.
Definitely try to find the SAIB, however, if you are interested in weapons and their employment. It has everything from full accessory lists for every small arm from the M9 to the Mk 19, plus Infantry MTOE's (useful even if you are not Infantry, I'm a 19 series Scout), ect. ect. ect. Good for PL's to look at, and for PSG's to *know.*
ETA:Not to sound like an ass, but one other thing the SAIB has in it is the 10m offset zero targets for the PEQ-2A and PAQ-4C. One look at those offset zero targets, and you'll see why Insight Technologies insists that both those items are designed to be mounted to the top of the handguard rail. The offset is... well, very very offset when using the side mounted option, it's much closer when top mounted.
Also, why the NODs on the weapon, if you've already got an IR aiming light mounted? The NODs do you no good there, as you can aim your weapon with the NODs mounted on your ACH and using the PAQ-4C, and this way, you don't have to point your weapon at everything you want to see at night... like your buddies next to you. It's generally considered rude
Just some friendly advice about the equipment, unless it's unit SOP, then leave it the way it is. Use your chain of command.
ETAII: No really, I'm not trying to sound like an ass!
Equipment is often misused, or not used to its full capability when people are unaware of how they're designed! Not trying to run you, or your platoon! Last thing I need is some of your NCO's howling at me!
Got enough of my own.