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How the Israeli’s use the TA31i ACOG

Previously I wrote about the TA31i ACOG that the Israeli’s use:
http://looserounds.com/2019/07/07/optic-of-the-week-trijicon-ta31i-israeli-issue/

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)
25-4
450
1007
20010
2500
300-20

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.

Bonus Mini Optic Tool of the Week: Troy Sight Tool

I had debating posting this up and seeing if anyone could guess what it was, but as far as I know, there are less than 6 that exist. Many of you would have immediately guessed it was a sight tool, but as to what sight, that would have been random luck.

The tool it self is very simple, a knurled piece of aluminum, 4 stainless pins, and a sling stud so you can put it on a lanyard or key-ring.

So what is special about this?

Long ago there was this company that made flip up sights for the AR15. They were called Troy Industries. Their flip up sights were considered the best and a necessary upgrade for a flat top rifle. No one would have considered having a serious use gun with out a quality metal BUIS. I used one of their rear sights while I was in Iraq. It is for this same rear sight that I got this tool for.

Now, I recall Troy Ind had multiple gaffs leading to a boycott of their products. That is probably why you have never heard of them, as we all know how effective conservative boycotts tend be. The last few Troy Industries products probably sit in the back of closets and in boxes in basements. No one would want to be seen with one of their products now. Certainly, the boycotts against Netflix and Walmart by conservatives will cause them to go out of business the same way.

But back to the tool. Early Troy rear sights had a stainless pin that locked the windage adjustment in one of the holes in the windage knob. You had to depress the pin each time for each “click” of windage. This was a pain in the ass, so someone started making these tools with the intent to sell them.

As it always tends to work out, as soon as someone comes up with a business idea, someone else pulls out the rug. Troy redesigned the sight to use a ball detent instead, changed the hole pattern, and included a slot so that it could be adjusted with a coin. Now you could easily adjust a Troy rear sight. Rendering this tool not only unnecessary, but completely useless for the new Troy sights.

Optic Mount of the Week: Scalarworks LEAP/MAG

Old annoying mount

Previously I talked about the Samson Aimpoint 3X magnifier mount I had. It was a minimal viable product. Sharp edges I cut my self on, repeatedly. When open it just sort of flopped around. It was very slow to attach or remove from a rifle. Quite frankly, it sucked. It made me not want to use the magnifier I own. This month I had decided to buy several of the items I wanted, and to sell of a bunch of stuff I wasn’t using. One of the items higher up on that list was a replacement for that damned Samson mount.

I was looking around at the multiple of options and quite a few people said that the Scalarworks mount is the very best. Once I saw the price tag, I had figured it had to be the very best since it was one of the most expensive options. I was pretty hesitant to shell out the money for it. If they are going to charge that much, it had damn well better be the best option out there.

This mount came vacuum sealed in a box with a clearly printed instruction card, and a hex drive torx wrench for the screws.

The ring is hinged at the top and bolted at the bottom. This makes for installing the magnifier very easy.

Instead of a cross bolt or throw level, Scalarworks mount uses a flush ratcheting knob. It is easy to use and the clicks are very positive. Loud too. The clamp is captive so it won’t come apart when you remove this from a weapon.

Lots of laser markings on the bottom. Looks like the individual units might be serialized.

Using this mount, like the factory Aimpoint mount, will require you to remove the rubber from the front of the Aimpoint magnifier cover. Don’t forget to degrease the inside of the ring and the outside of the magnifier before installation.

Putting the magnifier in the mount was very easy.

You can install the magnifier in the mount either direction, so you can have it flip left, or flip right. The clamping wheel will be on the side opposite of which it flips.

The Scalarworks LEAP/MAG mount is very quick to install or remove. Just give the knob a few turns. Not as fast as a throw lever, but fast enough.

The mount is very simple to use, and extremely small and light.

As for the flip to side, it is awesome. Unlike the sad and floppy Samson mount, this one has two ball detents securing it in the open or closed position. It takes a firm movement to flip the magnifier. Not hard, just firm. I can shake the rifle with the magnifier in place or flipped and it won’t move. I can pick up the rifle by the magnifier and shake it with out it moving out of the position it is in. Only with rotational movement then I can easily flip it in or out of place.

Now I haven’t used all the options out there, so I can not say if this is “the best” option out there. But it is damned good. I am glad I sold that old floppy Samson and upgraded.

Quick Reminder, Gooseneck Mounts Exist

For those of you that still have ARs with fixed iron sights, don’t forget that there is such a thing as a gooseneck mount.

There are a great many surplus gooseneck mounts out there. Some can be purchased for less than $10 shipped to you. I got the one pictured above for $8 shipped to me.

There are a few different heights, not all allow for using of iron sights, but they will let you mount a full sized reflex sight such an an Aimpoint, or Eotech (don’t use an Eotech).

Might not hurt to have one around.

OPTIC OF THE WEEK: Mark AR MOD 1 1.5-4x20mm

The Leupold MK AR 1x4x is a pretty nifty optic. With the increase in popularity of the variable power carbine optic and the increase in price that comes along with that popularity. The 1x-4x is no frills alternative that is still handy and versatile without the $1,800+ price.

opitc in a larue SPR mount on Colt 901

The scope has a 1 inch tube which is still the most common for most end users. It’s rapidly becoming passe, but it keeps the price down and few of the targeted market does not need a 30MM tube.

The adjustment turrets are Mils. instead of the MOA clicks. In addition, the elevation has markings to of a BDC to match common rounds used. Most come with the BDC for 55 grain M193 loads but you can order different ones from Leupold and swap them out. Not just in 5.56MM but also 309/7.62. The turrets have set screws that all you to reset the turret to 0 once you have it…zeroed. Which I clearly have not done yet.

The left side has the battery cap and control for the Firedot.

The reticle is a crosshair with a larger outer ring for use on lower power. The firedot lights up in the center of the crosshairs.

The reticle has carious marks for holdover etc. Armlist shows a diagram showing holds for M855 and a 175gr math load for .308. I have tried it and can confirm it is accurate.

best I could do

The power ring could be a little bigger, It is hard to grab and adjust in a hurry or with gloves.

The MK AR1-4x is usually seen on 556 carbines or rifles. The 1.5x with dot is meant to make it work as a RDS but it just can’t. We have not hit the point where we can have a true RDS then Variable magnification both in one optic yet. I do like this optic for “battle carbine” use. The combination works as a some what DMR.