How the Israeli’s use the TA31i ACOG


Previously I wrote about the TA31i ACOG that the Israeli’s use:

Quick recap, it is a 4x ACOG with a different reticle than the normal fare.

I was really curious about the markings and zeroing on this model ACOG. Recently I learned about how it was used.

Their TA31i ACOGs were mounted on ARMS quick detach mounts. This allowed them to switch between the ACOG and a night vision scope. The intent is that the night vision scope could be used at night out to 300m, and the ACOG as a day/night optic out to 500m.

The Israeli’s use a 250m zero on their rifles. They sight in 4 cm low at 25 meters using 62 grain ammo. This is suppose to give the following ballistics:

Distance (m)Drop (cm)

I was playing around the numbers in JBM ballistics and I am unable to recreate this reported trajectory.

There are pictures out there of this optic being use on rifles with 11.5, 13, 14.5, 16, and 20 inch barrels. Sometimes the optic is mounted on a flat top. Some times it is mounted on a rail installed on a carry handle. I wanted to find and post up some of these old pictures. But unfortunately I did not save a copy to my computer, and I think they were hosted on photobucket or tinypic or the like. They appear to be gone.

When I plug numbers in JBM ballistics, using 4 cm low at 25m on a M4 firing M855 would have the impacts constantly low. I just can’t see how these numbers work. I wonder if this was calculated from when the IDF was using 13 inch barreled rifles with carry handles.

Anyways, back to the topic at hand. Let us look at that reticle again:

The IDF designated marksman, sharing his notes, explains that the vertical lines on the far left and right of the reticle are for range finding using the size of a human head. The two longer vertical lines are the height of a human head at 200m. The shorter line is the height of a head at 300m.

They continue to explain that the width of the line between the two longer vertical lines on each side represents the shoulder width (commonly 19-20 inches) of a man at 400m.

The line between the shorter vertical line and the longer vertical line on the end is that shoulder width at 500 meters.

Now on a normal ACOG, the lines in the bullet drop chart represent a 19 inch wide width at the respective range in meters. This Israeli marksman was taught that on the TA31i ACOG that these lines represent the length from a persons back to chest (if they were facing perpendicular to you). So you have two ways to range a torso at 400 and 500m and a way to find the range if you can see the targets head at 200 and 300m.

I have a good many mixed thoughts about this information. No offense to the marksman who provided this information, but the trajectory numbers seem questionable to me.

In one way, I really like how you can range a head at 200-300m with out pointing the gun directly at the person. If you had their head lined up with one of those left or right ranging lines, the muzzle will be pointing a fair distance away from the individual.

When using this scope, I found I really liked having the horizontal line as it felt like it increased speed and ease of use. But I missed having a defined aiming point for 100m.


  1. I remember seeing pictures of them using an ARMS carrying handle rail and the ACOGs in the ARMS mount as well. It seemed cobbled together and uncomfortably tall, but, it works/worked.

    I’d love to see the manual the IDF issued with these. As for the ballistics I can only guess the IDF ordnance folks took a look at every possible way the scope would be used and averaged it out. Or, the ACOG was the only piece of a larger DMR program to survive through to adoption and no one changed the reticle or it couldn’t be changed? All purely speculation.

    Still a nice piece of kit.


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