View Full Version : ACOG's and reticle dimming
Doc Safari
05-14-14, 14:36
I can't believe no one has ever asked this before, but the threads I searched only turned up some responses that sort of touched on the issue. I didn't read the really long threads, but I thought it would have been addressed in a stand-alone thread of some kind.
One of the attractions of the ACOG is that you don't have to change batteries, but with the half-life of Tritium being only 12-15 years approximately, your reticle will eventually go dim and lose at least some of its usefulness in low light.
Now I'm not going to claim I'll still own ANY optic in 12-15 years, but let's just say I bought a TA11 or TA33 ACOG today, and not knowing for sure when it was manufactured, have to assume that some of the "half-life" has already ticked off.
When it reaches the first 12-15 year cycle's end, the reticle will dim by about half. Will it be all but unusable in low light then? Will I have to spend the coin to have the Tritium element replaced (and at the $500+ figure quoted in some threads maybe just go ahead and replace the whole optic)? Is "half" brightness still usable at night or in low light?
I am assuming a scenario where I might buy an ACOG today and either not have the funds to refurbish it in ten years, or to be in some SHTF scenario where "what you got is what you got."
I'm an "iron sight" guy right now, but I'd like to put away an ACOG for a rainy day. I have an Aimpoint T1 for everyday use.
That's the problem with using tritium. Reliable but not user serviceable.
With a Aimpoint in 10-15 years I'll go thru 2 or 3 batteries vs sending in the ACOG once.
Everything is a compromise.
H
It will still be usable at half brightness. It will be more than bright enough at dusk, which is likely the lowest light you will be able to shoot in, unless you are lucky enough to own a CNVD such as a PVS-24. I realize you could use something like a PVS-14, but most people don't own any form of NODs.
If an ACOG is what you want, don't hesitate. They are fantastic quality and bright enough. If you are worried, get one of the new battery powered models.
A cheap fix for decayed tritium is reportedly to tape a mini chemical light-stick over the fiber-optic on the top of the optic, although I personally have no experience with this method.
Does anyone have the info for a re-up on tritium? As far as pricing goes. TR-24 and a TR-22 2.5-10x56. Not dead yet but looking to the future...
ad_infinitum
05-23-14, 18:38
That's the problem with using tritium. Reliable but not user serviceable.
With a Aimpoint in 10-15 years I'll go thru 2 or 3 batteries vs sending in the ACOG once.
H
Trijicon wants a few hundred to swap the tritium reticle. Not very cost-effective.
Secondly, the brightest and longest lasting reticle color is green. It's still visible when red is dead. If you want brightness for the longest time, get any green reticle.
ad_infinitum
05-23-14, 18:40
A cheap fix for decayed tritium is reportedly to tape a mini chemical light-stick over the fiber-optic on the top of the optic, although I personally have no experience with this method.
+1 That might be your only option if you don't to upgrade or pay Trijicon for a replacement reticle.
This whole "never needs batteries" is not that great. I would rather swap one CR123A battery annually, over 10 years you will have spend probably $20 on batteries versus $300 for a reticle swap.
Unreconstructed
05-24-14, 07:45
Trjicon wants $500+ to recharge tritium in an ACOG. No thanks.
ad_infinitum
05-24-14, 07:53
They told me the same thing.
I will probably never buy another ACOG. Not cost-effective. Batteries make more sense. It's an optic that's good for 10-12 years and after that, makes more sense to buy another one. Cost-prohibitive.
I tried T1 and can see it's many advantages over any ACOG. Admittedly, it has disadvantages as well. I realize they are not even in the same class to compare.
The reticle is illuminated by fiber optic in daytime, and even with very low ambient light, the F.O. is still plenty bright to shoot with at dusk. Mounting a PVS-14 in front of a TA-31 is actually easier (in my opinion) to pick up with the reticle fully blacked out as opposed to any illumination at all.
My issued ACOG was made a while back and it's still plenty bright. I have almost 80-85% of the F.O. strip taped to prevent blooming, and even still, I can clearly pick the reticle up in low/no-light with the tritium. (although, honestly, no-light is a NODs and lasers world...)
I just took these two pics to show how much I have mine taped, and how easily distinguishable the chevron is with minimal ambient lighting indoors.
http://i1219.photobucket.com/albums/dd421/GTF425/IMG_3004_zps7ee4f7ea.jpg
http://i1219.photobucket.com/albums/dd421/GTF425/IMG_3006_zps11fc284d.jpg
It's a non-issue. Once again, the fiber optic illuminates the reticle in daytime, and the tritium is only for low/no-light. But, in the kind of lighting conditions you'd still be using a riflescope, the fiber optic can gather enough ambient lighting to do the job until you either A) transition to night vision/lasers or B) realize it's too dark to use an optic and wished you'd bought night vision and a laser.
If the possibility of tritium dying is keeping you from buying an ACOG, don't worry about it. They're incredibly tough, reliable, and easy to use. The 3.5x35 models have a more generous eye relief as opposed to the 4x32s which are something like 1.5", something to consider if anyone's seriously looking at purchasing an ACOG.
Doc Safari
05-27-14, 09:48
The 3.5x35 models have a more generous eye relief as opposed to the 4x32s which are something like 1.5", something to consider if anyone's seriously looking at purchasing an ACOG.
Yes, there's a really good write-up with pics showing the various eye relief distances here:
http://www.calguns.net/calgunforum/showthread.php?t=654467
Looks like the TA33 and TA11 have the best eye relief, in that order.
Good to know that green is the optimal color for maximum service life in the reticle.
It will still be usable at half brightness. It will be more than bright enough at dusk, which is likely the lowest light you will be able to shoot in, unless you are lucky enough to own a CNVD such as a PVS-24. I realize you could use something like a PVS-14, but most people don't own any form of NODs.
If an ACOG is what you want, don't hesitate. They are fantastic quality and bright enough. If you are worried, get one of the new battery powered models.
Sorry for the slight thread drift, but do you find that individuals are using ACOGs as their sole optic, or is the use of a small j-point sight or iron sights pretty much a given for most ACOG users? Thinking for 4x magnification. Is 4x alone serviceable as an all-around option or do you really need something else for close-up shooting?
steyrman13
05-27-14, 18:43
Sorry for the slight thread drift, but do you find that individuals are using ACOGs as their sole optic, or is the use of a small j-point sight or iron sights pretty much a given for most ACOG users? Thinking for 4x magnification. Is 4x alone serviceable as an all-around option or do you really need something else for close-up shooting?
They work fine as standalone. They were designed around the BAC Binding aiming concept. if you use a solid cover on the front it helps but it is similar to using a red dot at 50 yards and less
Sorry for the slight thread drift, but do you find that individuals are using ACOGs as their sole optic, or is the use of a small j-point sight or iron sights pretty much a given for most ACOG users? Thinking for 4x magnification. Is 4x alone serviceable as an all-around option or do you really need something else for close-up shooting?
I'm stuck using the TA51 mount, so all of our ACOG users have it as a stand-alone.
Within CQB distance, depending on lighting, I can use the vis laser on my PEQ-15 or just reflexive fire using the BAC. It's a training issue, and while the combination of the short eye relief and 4x magnification have a steep learning curve over a 1x, the advantage of magnification becomes apparent when having to ID threats. The issue with BAC is that it requires equal vision in both eyes to work well.
With as many low-power variable power optics as there are on the market today, you could go that route and not have to worry about it. But, if you go ACOG, it's just a matter of training. I can make hits almost as fast (if not just as...) the Aimpoint guys within 7m. The awkward distance for ACOGs is 7-20m in my experience, and that will come with range time. I'm sure the models with longer eye relief and different reticles can accommodate this style of shooting easier than the TA31RCO's chevron.
Reasons I like the ACOG:
Relatively low weight
Durability
Simplicity
Cons:
Fixed magnification
Short eye relief (4x models)
Cost
Appreciate the replies. I had done some searches and it seemed that most people online seemed to use some sort of alternate "CQB" site in conjunction with the Acog, but it seemed that most military users did not. Thanks for the clarification.
Sorry for the slight thread drift, but do you find that individuals are using ACOGs as their sole optic, or is the use of a small j-point sight or iron sights pretty much a given for most ACOG users? Thinking for 4x magnification. Is 4x alone serviceable as an all-around option or do you really need something else for close-up shooting?
The TA33 is easiest due its size, low power and huge eye box. But it obviously can be accomplished with the 4x and 3.5x.
soldier_twiggy
05-30-14, 09:45
They work fine as standalone. They were designed around the BAC Binding aiming concept. if you use a solid cover on the front it helps but it is similar to using a red dot at 50 yards and less
^^^This right here^^^ is the reason I'd run an Acog on all my AR's if I could afford it. But, it is how my 5.56 carbine is setup and it's super intuitive and quite accurate and gives the user "the best of both worlds" in one platform with the same cheek weld.
essayons
I might add (as I have thought about it) in even of EMP an Aimpoint or other battery illuminated sight will not work anymore. The ACOG will. Having said that I currently have an Aimpoint PRO but am looking at ACOGs.
Rayrevolver
05-31-14, 20:42
I might add (as I have thought about it) in even of EMP an Aimpoint or other battery illuminated sight will not work anymore. The ACOG will. Having said that I currently have an Aimpoint PRO but am looking at ACOGs.
You could you keep your prized electronics and a spare Aimpoint in an old microwave so EMP is not an issue.
Doc Safari
08-29-16, 16:08
(I should point out that long since this thread was posted I have purchased a couple of TA33 ACOG's).
I've been experimenting a bit under different lighting conditions. In pitch black darkness the reticle is pretty dim even on an ACOG I know has a good element. My older ACOG's element is just as bright, so I assume they're both good.
In low light (but not total darkness), varying degrees of ambient light make the reticle bright enough with the fiber optic, so that the tritium element is apparently not being utilized. (I say that because in low light the chevron is visibly brighter than it would be in total darkness-- meaning that something more than just the tritium is powering it).
Of course, without night vision (something I'll never be able to afford), a person probably would not fire into total darkness no matter how bright or dim the reticle is. So that level of dimness in the reticle would probably never be one that I would have to depend on.
Further, with my Surefire weaponlight illuminated, the reticle is about as bright as the tritium illumination in total darkness, and the target is illuminated to boot, obviously. I'm guessing the fiber optic is picking up just enough of the ambient light from the flashlight to illuminate the reticle (at least marginally acceptably). I haven't tried this with various backgrounds to see if the reticle washes out. Here in the sticks you see enough of the reticle with the tactical light on that you could hit a close-range target.
So, in total darkness, is the tritium useless to a person without night vision? I'm scratching my head thinking "maybe." You certainly would not take a chance on shooting at something you couldn't see no matter how bright the reticle is.
For a person such as myself who is forced to use a flashlight on the weapon to see the target, the fiber optic is evidently more important than the tritium--as long as it's picking up enough light to make the tritium unnecessary. As stated above, the miniscule amount of extra brightness in the reticle with the flashlight on versus the reticle alone in total darkness tells me the fiber optic is enhancing the brightness of the chevron.
Of course a scope with a black reticle is not going to be much use after dark even with the tactical light on. If the fiber optic were removed or damaged somehow, you would have a daytime scope, period. I tested this with a non-illuminated Nikon hunting scope and even with the flashlight on the reticle is invisible against a dark background. My TA33's red chevron is just bright enough to be usable.
I'm thinking of tweaking the amount of lumens in my tactical light to see if the fiber optic picks up more ambient light and becomes brighter, or if the extra light overwhelms the reticle and causes it to wash out to the point of being totally invisible. Some have suggested various ways of illuminating the fiber optic directly (like with a cyalume stick). But I wonder if there might be a "sweet spot" where a tactical light is just bright enough to be picked up by the fiber optic without washing out the reticle, and the target is sufficiently illumiated as well.
Anybody tried different levels of tactical light illumination to see how it affects your ACOG reticle at night?
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