HORRIBLE Accuracy with a TA31F ACOG?

[DyNo!]

On a good day, I can hold a 1" group at 25+ meters on irons. Although that isn't very remarkable, based on this; I'd think I'd be able to do it with a magnified optic at the same range.

The problem is, upon attempting to zero my new (used) TA31F, I shot a 4-5" group!

I thought shooting a magnified optics is supposed to allow you to shoot more accurately if not as accurately as iron sights do.

I took the TA31 off and confirmed zero with my MATECH BUIS on a standard 25 meter USGI zeroing target.

I consistently held it in the black.

What the f*#k? When I saw the holes appear in the target, I knew I wasn't shooting that badly! It's almost like the zero is wandering around due to phoria (Like I'm shooting the ACOG as an OEG but I'm not)!

I'm left eye dominant and I shot 4-5" groups with both eyes open and one eye open using the TA31. I shot less than 2" using the MATECH (although I can get it tighter with a smaller rear sight or red dot sights).

Does anyone have any answers because it's not a knockoff and it doesn't appear to have suffered any neglect.

I'm 20 and I don't have any eye problems that I know of.

(Pictures incoming)

Edited November 30, 2009 by DyNo!

[RufDog]

One thing with the ACOG- when you make an adjustment you need to firmly tap the dial before you put the cap on and shoot. If you are using a multi tool give the slotted dial a good 2 or 3 whacks. We use ACOGs on the All Guard team and this is a necessity. Also, I've seen more than one go bad and had it happen to me. Give that a try and if it dont work send it to Trijicon for warranty.

[DyNo!]

The ammo is reloaded pulled M193 junk mixed with tracers. (Don't ask , times are tough!)

3" 18? round group with TA31F:

3.25" With TA31F:

MATECH BUIS:

Less than .7" (Yes, I know it's only 3 and not 5 but I could have put 2 more in there eventually)

Edited November 29, 2009 by DyNo!

[G-ManBart]

Are you sure that you're not trying to snatch the shot when everything looks perfect? It doesn't seem like a lot, but 4X will let you see enough at 25yds that it can make people try to time the shot perfectly rather than just letting it break normally. Edit to add: I ask that also because the groups with the ACOG are quite a bit farther left and that's another possible sign that it could be a trigger control issue.

Have you tried it at 100yds to see if the trend is the same? R,

Edited November 28, 2009 by G-ManBart

[DyNo!]

Are you sure that you're not trying to snatch the shot when everything looks perfect? It doesn't seem like a lot, but 4X will let you see enough at 25yds that it can make people try to time the shot perfectly rather than just letting it break normally. Edit to add: I ask that also because the groups with the ACOG are quite a bit farther left and that's another possible sign that it could be a trigger control issue.

Have you tried it at 100yds to see if the trend is the same? R,

I was shooting with about 7 points of contact so I doubt I would have been able to jerk it that much. I never broke a shot outside of the blue circle.

I didn't bother properly zeroing the scope because the 5 shot groups were so big so the POI might not be relative to the POA. The 5 shot groups aren't pictured but they look like the one on the 25 meter target. It could be though.

I'll be going out to the range again in a few days with some better ammunition and I'm going to push the target to 100. I just hope I'm on paper.

Edited November 28, 2009 by DyNo!

[Jadeslade]

When I first got my TA01NSN (4x32) I had the same problem. I called Trijicon and they said to take it off, remount it making sure that the eye relief is about 1 1/4 inch, basically nose on charging handle as usual. I am sure you have done this, I think they can sometimes take some settling in. I am left eye dominant , but I shoot with both eyes open on rifles with my right eye as primary-took a while, kind of like shooting with left hand. I know this is nothing new-just thought you might like the info-it will probably settle in the next time you shoot.

[DyNo!]

When I first got my TA01NSN (4x32) I had the same problem. I called Trijicon and they said to take it off, remount it making sure that the eye relief is about 1 1/4 inch, basically nose on charging handle as usual. I am sure you have done this, I think they can sometimes take some settling in. I am left eye dominant , but I shoot with both eyes open on rifles with my right eye as primary-took a while, kind of like shooting with left hand. I know this is nothing new-just thought you might like the info-it will probably settle in the next time you shoot.

Thanks, I've got 300 rounds that I'm going to burn tomorrow so I'll see what happens and report back.

[DyNo!]

Went out again today.

Here are the three targets I shot at 100 yards:

I let two other people shoot the rifle and here were their targets. One of them used their own ammo and one of them used mine - I forgot which.

Shooter 1 (POA IS BLACK SILHOUETTE ON BOTTOM):

Shooter 2 (POA IS BLACK SILHOUETTE ON TOP):

All three of us said we didn't break a shot outside of the black despite the groups being much bigger. We all agreed that there was no way we were shooting like this, the scope was lying to us.

The screws are all tight on the bottom of the mount. The knobs were tight on the rail. The ammo I shot was my 55gr blaster reloads. One of the other shooters shot M193. I was able to keep all of my groups around 1.5-2.5" with iron sights at 100 yards even with my shitty ammo, bad aim, and small targets.

I guess I'm going to call Trijicon.

Edited November 29, 2009 by DyNo!

[DyNo!]

After thinking about it for a little while, it appears I might have reached the limitation of my ammunition. Looking at the target in this picture, the group measures 2.25MOA (I assume this was the one using factory M193):

The other (using my ammo I presume) measures 3.1 MOA:

This one using iron sights at 25 meters using my ammo converts to 2.73MOA:

There's only one way to find out...

Edited November 30, 2009 by DyNo!

[3gunner]

With that ammo 2" is all you should expect. Buy a couple of boxes of Black Hills 68 gr , Fed Gold Medal ,or Tap and see what happens.

edit to add: If you have trouble with the chevron put some painters tape on it to make it black or use 300 M cross hair and aim low on the target.

Edited November 30, 2009 by 3gunner

[diablodawg]

Consistant eye relief and paralax are a big problem I see with my Marines. Ensure you don't have a black shadow on the edge of the lens as you are looking through it. Also, after you make adjustments, give it a few good whacks with something hard.

[DyNo!]

It was the ammo after all.

I had some Lapua 55 grain bullets sitting around so I made some "good" ammo.

.925 MOA @ 100 Yards with the Lapua 55gr ammo:

3.74 MOA @ 100 Yards with machine pulled 55gr milsurp bullets:

2.5 MOA @ 100 Yards with machine pulled 55gr milsurp bullets:

[Leozinho]

I'm certain it was your ammo, too. However, one small factor could have been that the scope may have settled as you shot it more.

I've seen ten guys on the firing line with ACOGs, all of them chasing the zero and never understanding why they where having problems zeroing. If I need to move 3 clicks to the right, I will move it ten clicks to the right and then seven clicks to the left. I also tap the turrets with my Swisstool, too. In my limited experience, the ACOGs don't do small adjustments well.

Another good habit is to make sure the scope is seated forward against the rail. Apply forward pressure as you tighten the screws down. Due to recoil, the scope is going to work it's way to that position anyway. Might as well start of with it like that. I don't know how much that effects a AR shooting mil-surplus ammo, but the best long range shooter I've met taught me to do that for a sniper rifle. So it's probably a good habit to get into.

[DyNo!]

In my limited experience, the ACOGs don't do small adjustments well.

I know that's right.

That 1 click = 1/4 MOA @ 100 is bullshit.

[Les Snyder]

try some factory S@B 55g. I have an older TA01 4x32 on a Rock River 16 inch. It will shoot 1inch at 200m and the trajectory curve is calibrated to the 200, 300, and 400 m stadia lines. In little wind it shoots equal to my hand loaded 69 Sierras. I had a pretty good run on stage 1 at Ft Benning.

regards

Les