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9/23/2020 3:47:02 PM
Posted: 10/16/2008 3:09:33 PM EDT
on the RCOA4 ACOG? Like at 200M, 100M and 300M?
Link Posted: 10/16/2008 3:46:23 PM EDT
Not sure I follow you.  You zero it at whatever distance on the tip of the chevron.



Zeroed at 100m the line with the 4 is POI at 400m, the 6 is POI @ 600m, bottom line is POI @ 800m.
Link Posted: 10/16/2008 3:50:42 PM EDT
[Last Edit: 10/16/2008 3:51:07 PM EDT by TheJeanyus]

Originally Posted By platypusREX:
on the RCOA4 ACOG? Like at 200M, 100M and 300M?

Zero at 100, use the tip all the way out to 200, and use the bottom of the chevron at 300.  At least, that is my understanding.  My local range only goes out to 100 yards.
Link Posted: 10/16/2008 3:56:15 PM EDT
400 through 600 is easy. What distance is the little red segment? If the tip of the chevron is 100, where is 200?

This one I understand.
Link Posted: 10/16/2008 5:01:21 PM EDT

Originally Posted By platypusREX:
400 through 600 is easy. What distance is the little red segment? If the tip of the chevron is 100, where is 200?

This one I understand.
i36.tinypic.com/i5172q.jpg

The tip of the chevron will still be "good enough for government work" at 200 yards with a 100 yard zero, I'd imagine.
Link Posted: 10/16/2008 5:40:24 PM EDT
Stolen from the internet somewhere. I don't know where Or I'd give the guy credit. It's a great write up.

I’ll be going over my experience with the Trijicon ACOG, how it works and why it’s such an awesome optic.  The particular ACOG that I will be talking about is the 4x32 red chevron scope.  4x is enough magnification to get high chest shots out to 800 meters, and low enough to prevent tunnel vision.  The model number is TA31F.  The ACOG was developed for the military as a force multiplier allowing troops to identify, range, and engage targets out to 800 meters and still be useful for CQB.  The ACOG has internal elevation and windage adjustments and uses a tritium assisted illuminated reticle that does not rely on batteries.  It uses the BAC (Bindon Aiming Concept) and was designed to be used with both eyes open.  The reticle is calibrated for military/shelf .223 or 5.56x45mm, so if you plan to hand load for your AR this might not be the best choice for you.  This scope was designed for combat and is not the best choice for hunting because its range finding reticle was designed to range us not game animals.

Long Range Shooting with ACOG and Range Finding
Long range shooting with the ACOG will explain itself if I explain how they designed the reticle pattern.  Looking through the scope the first thing you will notice is the bright red chevron.  Under the chevron is a vertical post which the top tip is also illuminated.  The next things you will notice are five crosshairs that run perpendicular to the vertical post.  The first line has a 4 to the right of it, and then the numbers skip a line to the 6.  The line between the labeled 4 and 6 is 5 but they didn’t include the extra numbers to stay away from cluttering things up.  The last two lines at the bottom are 7 and 8.  Everyone still with me?  Good.  
The very tip top of the red chevron is your aiming point for anything 100 meters and closer.  The illuminated tip the vertical post is your 300 meter aiming point.  There is no 200 meter aiming point so be aware of this, you might just have to judge it.  The two bottom tips of the red chevron represent 19 inches from tip to tip at 300 meters.  Each line represents 19 inches across at that range.  This means that the 4 line represents 19 inches at 400 meters.  The next line down which is the 5 line is 19 inches wide at 500 meters and so on all the way down to the bottom line which is 19 inches at 800 meters.  They do this because 19 inches is the average width of a man’s shoulders. To find the range of your target all you need to do is measure his shoulder width using the lines or the chevron.  When you find the one that fits use that aiming point and pull the trigger.  If no lines fit the man out in front of you all you need to do is estimate between the line that is too big and the one that is too small.  Correcting for windage is somewhat of a problem because of the internal adjustments.  You have to use Kentucky windage at longer ranges with high winds.
Close Quarters Combat with the ACOG
Remember how I said this scope could be used for both long range shooting and CQB.  This is because the ACOG uses the BAC (Bindon Aiming Concept).  If you thought ranging was easy this is even easier, although it takes a little more training to get used to the BAC.  This scope was designed to be used with both eyes open and when you do this you take advantage of the BAC.  For room to room clearing all you need to do is look at the red chevron with both eyes, and the scope housing will almost disappear leaving you with a view of a bright red chevron.  Put the chevron on the target and pull the trigger.  Sounds like a red dot sight now doesn’t it?  You might notice a little magnification but with training it becomes unnoticeable and second nature.  As a good rule of thumb try and shoot anything closer than 300 meters with both eyes open.  For targets farther than 300 meters go ahead and use one eye since 300 meters and farther is considered a precision shot for an assault rifle.
The illuminated reticle is very effective at night time, but during day time it gets almost too bright.  A piece of green duct tape over the orange fiber optic will dull the chevron out and you’re golden.  When you need more illumination just rip off the tape.  That’s my low down on this great piece of gear.
Link Posted: 10/16/2008 5:46:47 PM EDT

Originally Posted By TheJeanyus:

Originally Posted By platypusREX:
on the RCOA4 ACOG? Like at 200M, 100M and 300M?

Zero at 100, use the tip all the way out to 200, and use the bottom of the chevron at 300.  At least, that is my understanding.  My local range only goes out to 100 yards.


Tip is 100

Inside V of chevron is 200

Top of Post is 300.
Link Posted: 10/16/2008 6:04:21 PM EDT
[Last Edit: 10/16/2008 6:04:47 PM EDT by 1911_Mitch]


Tip is 100

Inside V of chevron is 200

Top of Post is 300.


The above is worth repeating
Link Posted: 10/16/2008 6:18:41 PM EDT

Originally Posted By Postal0311:

Originally Posted By TheJeanyus:

Originally Posted By platypusREX:
on the RCOA4 ACOG? Like at 200M, 100M and 300M?

Zero at 100, use the tip all the way out to 200, and use the bottom of the chevron at 300.  At least, that is my understanding.  My local range only goes out to 100 yards.


Tip is 100

Inside V of chevron is 200

Top of Post is 300.

Thanks.
Link Posted: 10/16/2008 6:27:17 PM EDT
Zero at 100.

Each click is 1/3 of an inch at that distance.

Remember to hit the optic after you make an adjustment.
Link Posted: 10/16/2008 6:41:27 PM EDT
A nice pix from Trijicon may help




Link Posted: 10/16/2008 7:24:28 PM EDT

Originally Posted By scottrh2:
A nice pix from Trijicon may help

i139.photobucket.com/albums/q319/amynruss/Technical1.jpg

i139.photobucket.com/albums/q319/amynruss/Technical2.jpg


Now that about sums it up.
Link Posted: 10/16/2008 7:30:35 PM EDT

Originally Posted By scottrh2:
A nice pix from Trijicon may help

i139.photobucket.com/albums/q319/amynruss/Technical1.jpg

i139.photobucket.com/albums/q319/amynruss/Technical2.jpg


Would you have one of those for the donut reticule.
Link Posted: 10/16/2008 7:47:06 PM EDT
No, just the mil spec chevron.  I would think that they would be just the same.
Link Posted: 10/16/2008 8:07:24 PM EDT

Originally Posted By platypusREX:

Originally Posted By scottrh2:
A nice pix from Trijicon may help

i139.photobucket.com/albums/q319/amynruss/Technical1.jpg

i139.photobucket.com/albums/q319/amynruss/Technical2.jpg


Would you have one of those for the donut reticule.


Top 100
Middle 200
Bottom 300 (dunno if its top of bottom or bottom of bottom)
Link Posted: 10/16/2008 9:20:07 PM EDT
those measurements only apply, if you're using 62gr M885 right?
Link Posted: 10/17/2008 4:53:14 AM EDT

Originally Posted By A96HondaAccordEX:
those measurements only apply, if you're using 62gr M885 right?


TA31 is 55gr ammo out of a 20 inch rifle mounted on carry handle

TA01NSN is 62gr ammo out of a 14.5/16 inch carbine mounted on flattop.


Either way, often the difference between your actual point of impact and the aiming it less then the thickness of the aiming line at that distance.  Any .223 ACOG for any .223 setup will be close out to about 500 yards.
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