Rifle Scopes How bad is eye relief on ACOG 4x?

[JelloStorm]

I want to put an ACOG TA31 on my new Bushmaster M4, but they list the eye relief at 1.5" and that is not a lot.

Is it really that bad to work with?? I see people with them all the time so they can't be that shitty, but seriously only 1.5 inches eye relief? That would suck on anything bigger than 5.56.

Anyone got a pic of through the scope on the TA31 RCO model?

 

[d90king]

Re: How bad is eye relief on ACOG 4x?

Since most guys run them on AR's the 1.5-2" works okay as they are normally shooting nose to CH... If you aren't, then yeah, the eye relief could be a problem.

I don't care for them personally but everyone has different taste in glass. I have found a simple T1 allows me to make hits on steel out to 550 yards and thats out of a 14.5 Noveske. I use a 3x mag behind it if I really need to be a bit more precise...

 

[yoda1988]

Re: How bad is eye relief on ACOG 4x?

I have a TA31f... the eye relief isn't great but most ACOGs are calibrated for 5.56. There are some made for the 7.62. When shooting an AR or other 5.56 rifle, you won't have any problems. The TA31 does its job, and it does it well. At first I was hesitant because of the price, however, once the ACOG was mounted, I never looked back. I'm thinking of getting another if the price is right.

 

[JTinIN]

Re: How bad is eye relief on ACOG 4x?

I like the 3.5 TA11 series better myself with a fixed stock AR15/M16. With a carbine you can move the stock in a click if needed.

The 3.5 TA11 series is larger has less field of view and lower power, so one's pays your money and takes you choice.

 

[ORD]

Re: How bad is eye relief on ACOG 4x?

Since its going on an AR-15, as long as you shoot nose-to-the-charging-handle, the eye relief is a non-issue. I have been running a TA31F on one of my M4's for several years and it works great.

 

[EricCartmann]

Re: How bad is eye relief on ACOG 4x?

I have 3 ACOGs, the TA01-NSN, TA31F, and TA11F.

To me ACOGs are the best bang for the buck. I have never seen glass (on 4x mode) that beats the ACOG.

To this day, I am still amazed how such a small package can deliver so much. The FOV of huge on 4x ACOGs! Not just that but an ACOG is basically bomb proof.

The Short Eye Relief on the 4x ACOGs (TA01, TA31)is not a problem for AR15 Shooters that shoot nose to charging handle, which is how most of us in the Army were taught. So ACOGs are natural for us.

Also the kick on a 556 gun is mild enough to that the ACOG won't hit your goggles when the gun recoils, and even if it does, just extend your stock one notch and that fixes that.

Now if you are shooting .308, I would not recommend the 4x ACOGs, instead go 3.5x, the TA-11 series. That extra inch of eye relief is huge and makes the gun so much easier to use. The TA-11F is now my favorite ACOG. You can even use the TA-11F on a 147gr .308 even though the reticle is calibrated for 62 gr .223. It will good out to 600 yards and only be off a couple of inches in drop (according to the ballistic calculator).

The negative of TA-11's is the mag is slightly less, the FOV is slightly less, and it is heavier.

Pick your poison when it comes to ACOGs, they all are great.

I even have an ACOG on my dedicated .22 gun

 

[JelloStorm]

Re: How bad is eye relief on ACOG 4x?

Why do you have Aimpoints in front of the ACOGs?

 

[EricCartmann]

Re: How bad is eye relief on ACOG 4x?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JelloStorm</div><div class="ubbcode-body">Why do you have Aimpoints in front of the ACOGs? </div></div>

It's canted in case I want to use red dots without changing my cheekweld. Just rotate the gun about 15 degrees and now you have a red dot that can accurately make hits.

 

[chalwie]

Re: How bad is eye relief on ACOG 4x?

Another option, TA-33G. Better eye relief, I can see well with VLTOR stock fully extended but slight tunnel effect. At 2nd extension, I can see full FOV.

 

[JelloStorm]

Re: How bad is eye relief on ACOG 4x?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: EricCartmann</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JelloStorm</div><div class="ubbcode-body">Why do you have Aimpoints in front of the ACOGs? </div></div>

It's canted in case I want to use red dots without changing my cheekweld. Just rotate the gun about 15 degrees and now you have a red dot that can accurately make hits. </div></div>

Now that you mention that, I do see the slight cant on the Aimpoints. That's fuckin brilliant man. You got some nice setups.

Would you go TA31A with the triangle or the TA31-RCO ?

 

[EricCartmann]

Re: How bad is eye relief on ACOG 4x?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JelloStorm</div><div class="ubbcode-body">
Now that you mention that, I do see the slight cant on the Aimpoints. That's fuckin brilliant man. You got some nice setups.

Would you go TA31A with the triangle or the TA31-RCO ?
</div></div>


Wish I could take credit for it, but I got the idea from seeing it multiple times on AR15.com. It works and is very natural. There are haters to this setup, but that's only because they never tried it.

 

[EricCartmann]

Re: How bad is eye relief on ACOG 4x?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: chalwie</div><div class="ubbcode-body">Another option, TA-33G. Better eye relief, I can see well with VLTOR stock fully extended but slight tunnel effect. At 2nd extension, I can see full FOV. </div></div>

FOV on TA-33 is only 19ft vs. 34ft for the TA-31. Which means everyone is watching a 60" widescreen while you are oly watching a 30".

Also Mag is 3x compared to 4x for the TA31. It is noticeable side by side. Also the mount that the TA33 comes with sits really high, I have no idea way.

 

[EricCartmann]

Re: How bad is eye relief on ACOG 4x?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JelloStorm</div><div class="ubbcode-body">

Would you go TA31A with the triangle or the TA31-RCO ?
</div></div>

The reticle on a TA31A was calibrated for carry handle mounting. I don't recommend to mount an ACOG on a carry handle, it looks retarded and your cheek weld won't be as good.

The RCO is what the Marines issued. Price for those always seem to high, an alternative I think is the TA-31H or TA-31F, both are about $200 cheaper and only thing different is the reticle. Both the F and H comes with a flat-top mount and their reticles are calibrated for 14.5" barrels shooting M855, 62 gr ammo.

 

[JelloStorm]

Re: How bad is eye relief on ACOG 4x?

I remember seeing a write-up by someone who took a whole bunch of ACOGs and wrote out how best to zero them on different AR platforms.

Can't remember which site I found it on and was unable to find anything.

Anyone know where I can find it?

 

[ORD]

Re: How bad is eye relief on ACOG 4x?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JelloStorm</div><div class="ubbcode-body">I remember seeing a write-up by someone who took a whole bunch of ACOGs and wrote out how best to zero them on different AR platforms.

Can't remember which site I found it on and was unable to find anything.

Anyone know where I can find it? </div></div>

There have been a couple of different threads along those lines, but here is the one I think you are talking about:

http://www.ar15.com/forums/topic.html?b=3&f=18&t=229420

Also, here is another good comparison thread for ACOGs:

http://www.militarywarfighter.com/Trijicon_ACOG_Comparison_and_FAQ_s/386.htm

 

[JelloStorm]

Re: How bad is eye relief on ACOG 4x?

ORD,

Thank you sir! That first link was exactly the one I was looking for.

So a TA31A on an A3 14.5" is almost the same as the 16" firing M193. Guess I should be fine with that.

Where would your point of impact be on the Triangle, or Chevron for that matter? Very top tip or in the middle like the Donut of Death?

 

[ORD]

Re: How bad is eye relief on ACOG 4x?

It will be something like this (with the TA31F) assuming that your rifle's MV, height over bore, etc. match up with those figures used by BR in his article:

100yds - Zero for 1" above the tip of the Chevron
200yds - 0.3" higher than the bottom of the chevron's inverted V
300yds - 0.7" lower than the tip of the line at the base of the chevron's inverted V
400yds - within 4" of POA using the reticle
500yds - within 5" of POA using the reticle
600yds - 10" lower than the 600yd mark on the reticle

Again, the only way to know if this data matches up is to actually do it with your rifle and record your results. The pic above is just by way of example. Looking through the reticle and keeping in mind the variations listed by BR you will be able to determine the best POA/hold-over.

 

[samnev]

Re: How bad is eye relief on ACOG 4x?

I also own a number of 4X ACOG's. The short eye relief on the ACOG's does take some getting use to. If your concerned take a look at the 3X TA33R it has longer eye relief and easier to use IMO.

 

[JelloStorm]

Re: How bad is eye relief on ACOG 4x?

Can't wait to get one. Just not looking forward to the $1k pricetag.

 

[EricCartmann]

Re: How bad is eye relief on ACOG 4x?

You can use any ACOG for any gun and you will find out the BDC comes close. If you want exact values, a ballistic calculator is your friend.

The BDC is just an approximation anyways. It is calibrated for a particular bullet weight, going at a particular velocity, with the scope mounted a particular weight above the bore.

Here are my calculations for TA11-F on an AR10 shooting .308 147gr ammo leaving the barrel at 2670 fps:

-----------------------------

Here is the data I used:
ACOG 2.7" over bore
.304 BC for M855 (62gr .223) projectile
.391 BC for M80 (147 gr .308) projectile
2900 FPS for M855, velocity of M855 out of 14.5" barrel.
2680 FPS for M80, velocity of M80 ut of a 16" barrel.


Now using the ACOG TA-11F BDC (designed for M855 out of M4) with M80 out of a 16" AR10 my BDC will be off as follows.

100 yards: dead on
200: 1/2" too low
300: 2" too low
400: 3" too low
500: 3" too low
600: 3" too low
700: 1" too high
800: 8" too high

 

[JelloStorm]

Re: How bad is eye relief on ACOG 4x?

If I were you, I'd shift my POI about 1.5" up and simplify those shots a lot.

As much as I want the triangle, I'm not sure how to range someone with a solid triangle as compared to the chevron found on the RCO optic.

If it's good enough for the Army and USMC, then it's sure as hell good enough for anything I'd ever use it for.

Except zombies. Fuckin ZOMBIES...