Hello gents,

I am doing research on acog’s for my AR. It has a 16” barrel. What is a good match in y’all’s opinion. I’ve got little experience with them but from what I’ve read they are solid. I like the 4x32 USMC version and the Primary Arms Acss.  Thanks for any advice.

I picked up a couple of the TA31's from the cancelled Marine contract a few years back. Really like them. At the time you could get them with the pouch, cleaning kit, flashkill for $850 OTD if you dickered a bit. THAT was a good show. [2 TA31's, a police 870, $250? [can't remember exactly] a K .45 ammo and a Colt MKIII 4'' revolver.]

TA31F has a reticle calibrated for M193/M855 from a 16” barrel IIRC.

The ACSS Aurora manual has recommended zero ranges for most common loads for barrels from 14.5" to 20".  It's an impressive reticle.

I'd go with the TA31F.

Any of the .223’s, or really .308’s, are going to be close enough. If you’re super worried they do have a 193 specific reticle and one that’s a blend of 14.5/20” (whatever that means)

I played with all the ACOG models and VERY MUCH preferred the TA11. I got the green donut reticle, but now a days people prefer the green horseshoe reticle. The TA11 by far has the best field of view and extremely generous eye relief. The quality of the glass is phenomenal.

Myself and others have had great luck with the TA11C .308 carry handle mount using 16" barrel and 75 to 77gr 5.56 pressure ammo.
It is essentially a dead on match.

The 11 has considerably less FOV than the 31, it does have around an inch more eye relief.

Yeah a lot of times .308 lines up closer to heavy .223, owing to the lower velocity and higher BC.

But the .308 flat top models don't line up near as well as the .308 carry handle models mounted to the flat top receiver.

I have the TA31-G-ACSS from primary arms on my main 16inch AR and really like it.  Everyone that shoots it loves it.  I'd get another if they weren't so expensive.

TA-110.  LED.  You can dial in the exact illumination you need.  No tritium to replace.

^^^^ what that guy said.  LED is a huge improvement.

Browe BCO - no need to dial in brightness, the optic does it for you.  (4x32 a la TA-31 though.)

TA11 is my new fav

I have a TA01 with the 308 reticle. Was planning on building my first Grendel or 308 with it....oops. That ammo ship has sailed for the time being. I'm now going to put it on a 16 or 20 inch 223 upper. You're saying I should go with the carry handle mount over the quick release mount I have? This model allows me to use iron sights if attached to carry handle.

No, the .308 models ballistically calibrated for the carry handle are more accurate when mounted via TA51 adapter (or LaRue, ARMS etc) on flat top of a 16" shooting 5.56 75/77gr ammo than any other models.
I find the TA11C to be a near perfect match for 77gr 5.56 ammo (Mk262) from my suppressed (OPS 12th) 16" Recon out past 600 meters.
Your TA01 should have the exact same ballistic reticle.


From the B Roberts ACOG BDC Chart:
.308 Carry-Handle BDC

This BDC is based on a carry handle ACOG firing M852 Match out of a 20" barrel.

ACOGs using this BDC include the TA11C and TA01B.

Stats used to figure BDC baseline: M852 traveling at 2,500fps with a BC of .447 and a height over bore of 3.5"



For a Flattop 20" barrel firing M852:

Sight in at 150 or 0.7" high at 100. You will not deviate more than 0.5" from the BDC all the way out to 600



For a Flattop 20" firing 75gr OTM @2750fps

Sight in at 100 per manual. You'll be dead on to 200, 1" high at 300, 3" high at 400, 6.7" at 500, and a bit over 10" high at 600.



For a Carry Handle 20" firing 75gr OTM

Sight in at 100 per manual. This doesn't match the .308 BDC too well; but it is the best you'll get. 1" high at 200, 3" high at 300, 5" high at 400, 10" at 500 and 15" high at 600.



For a Flattop 16" firing 75gr OTM @2615fps

Sight in at 100 per manual. This is a real close match. Max deviation is 2" at 600m and you'll be within 1" at all other ranges.



For a Carry Handle 16" firing 75gr OTM

Sight in at 100 per manual (for a slight edge, sight in at 125 but if you are good enough to notice the edge, then you probably want a more precise match anyway. You'll be about half MOA out to 600.
There is no data for other .308 rounds or 68gr OTM because I don't have the necessary info to figure it out. If somebody gets me the 68gr info I'll add it; but those wishing SMK data or additional .308 data will need to run the numbers themselves (although I can offer help if you need it).

There is no data for 55gr or 62gr because the .308 BDC is by and large a bad match for these rounds.

As you can see the .308 BDC is an excellent match for the 5.56mm 75gr OTM in most applications.

The TA11E uses a flattop adapter. If the BDC is designed for flattop mounting (2.5" height over bore), this ACOG will be more difficult to match to 75gr OTM use. Use the sight-in procedures given for the regular .308 BDC but figure an extra 1" high at 200, 2" high at 300, 3" high at 400 and so on.

Great info on the .308 BDC in this thread. I can confirm the near ballistic match of 77gr match projectiles with .308 ballistics having shot both head to head out to 1k.

As for ACOGs the 31F is great for light stuff, use the info above to choose a .308 reticle for heavies.

I like the TA31H-G

The 5.56 flat top reticles do fine with MK262 if you zero it at 300M on the 300M hash.  I recommend zeroing any ACOG or BDC like that.

can i hijack to ask the same question but for a 12.5" (.223 wylde, 1/8, 55gr ball mostly)?

As a generality: when in doubt, spread it out. Your BDC is going to be more ‘arched’ than most ACOG BDCs due to lower BC and MV. This won’t really matter inside 300, but falls apart fairly fast past there. Mitigate this by being realistic about the ranges you’ll be shooting, and splitting the difference between the min/max of those ranges.

Example: you’ll be using this within 300m. Zero for the BDC intersecting your actual trajectory @ 200. This makes the BDC the closest throughout that range, instead of being perfect on one end and way off on the other. A ballistic calculator will help here, or you could just zero 1-1.5” high @ 100m like I do in these scenarios, since I’ve found it usually ends up being 6 of one and 1/2 dozen of the other.

Don’t worry about this too much, whatever you do will get roughly three same result.

I answer this question every few weeks.  All you have to do it look at this post:
https://www.ar15.com/forums/ar-15/Bartholomew_Roberts-Big-ACOG-BDC-Chart/18-229420/

I run a TA33 on my 12" SBR

@edwin907

You rock. Thank you sir.