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Got my new Trijicon ACOG TA-31RCO M4, something seems off...
6/4/2012 6:19:45 PM
I got my new TA-31RCO M4 today from Larue, everything looked great as expected with a $1400 piece of glass. But after I got home from zeroing it at the range, I noticed that the right side horizontal mil scale was very blurry while the left side horizontal mil scale was crystal clear. I made sure the lenses were clean and looked again, still blurry. I used these exact optics while i was in the corps so I am relatively familiar with them, and I dont remember having this issue with the reticle setup. Is this normal? Thanks in advance.
The red circled area is what I am trying to describe as being very blurry.
The red circled area is what I am trying to describe as being very blurry.
6/4/2012 6:28:59 PM
That's normal. Something about a lens being slanted so the entire reticule will not be perfectly clear. I believe the manual specifically says why.
Trijicon FAQs explains why.
Yes. The reticle pattern in the ACOG is formed by removing highly reflective metal from a prism mirror. This mirror is at about a 45-degree angle inside the gun sight. This means that the left side of the reticle is closer to the eye than the center of the reticle and the right side of the reticle is further from the eye. The result- the right side of the reticle is focused beyond infinity which can cause distortion on the right side of the reticle. The perceived distortion will be more or less depending on an individual's eyesight. The left side of the reticle is unaffected because the human eye has no difficulty focusing on a closer object. This in no way detracts from the performance of the scope. The image of the target area is not affected. Only the right hand side horizontal reticle line is blurry. This construction is required to achieve a parallax free vertical center of the scope, which allows the built in ranging on the reticle pattern.
Trijicon FAQs explains why.
Yes. The reticle pattern in the ACOG is formed by removing highly reflective metal from a prism mirror. This mirror is at about a 45-degree angle inside the gun sight. This means that the left side of the reticle is closer to the eye than the center of the reticle and the right side of the reticle is further from the eye. The result- the right side of the reticle is focused beyond infinity which can cause distortion on the right side of the reticle. The perceived distortion will be more or less depending on an individual's eyesight. The left side of the reticle is unaffected because the human eye has no difficulty focusing on a closer object. This in no way detracts from the performance of the scope. The image of the target area is not affected. Only the right hand side horizontal reticle line is blurry. This construction is required to achieve a parallax free vertical center of the scope, which allows the built in ranging on the reticle pattern.
6/4/2012 8:51:25 PM
Thanks for the info. Im glad to see that this is normal.
6/4/2012 11:09:15 PM
Normal, it is due to the angle of the lens inside.
6/4/2012 11:55:13 PM
I am at ease now. I almost freaked out.
6/5/2012 10:55:01 AM
Originally Posted By Semper_Firearms:
I am at ease now. I almost freaked out.
I am at ease now. I almost freaked out.
When I first got my TA31 I almost freaked out too... pissed me off. It is something about how it "focuses beyond infinity"... sounds stupid... you can't have anything beyond infinity by definition; it's like people who say that parallel lines can touch in some freakish circumstance out in the vacuum of space.
6/5/2012 1:51:49 PM
You can even see a little of the blur in the Larue pic. 
I am looking through the TA31RCO-M4 I was issued, and I definitely can't focus on the farthest right side tic marks.
The effect gets a lot more noticeable if you use a short depth of field on the camera. The left side of the reticle is too close and the right side is too far in this shot I took a few weeks ago.
(The Afghan countryside is quite brown.)
I am looking through the TA31RCO-M4 I was issued, and I definitely can't focus on the farthest right side tic marks.
The effect gets a lot more noticeable if you use a short depth of field on the camera. The left side of the reticle is too close and the right side is too far in this shot I took a few weeks ago.
(The Afghan countryside is quite brown.)
6/5/2012 2:17:24 PM
Originally Posted By thornejc:
When I first got my TA31 I almost freaked out too... pissed me off. It is something about how it "focuses beyond infinity"... sounds stupid... you can't have anything beyond infinity by definition; it's like people who say that parallel lines can touch in some freakish circumstance out in the vacuum of space.
Originally Posted By Semper_Firearms:
I am at ease now. I almost freaked out.
I am at ease now. I almost freaked out.
When I first got my TA31 I almost freaked out too... pissed me off. It is something about how it "focuses beyond infinity"... sounds stupid... you can't have anything beyond infinity by definition; it's like people who say that parallel lines can touch in some freakish circumstance out in the vacuum of space.
A lack of comprehension on your part does not make the subject itself "stupid."
