View Full Version : Laser bore sighters, NVG optics.
bsmith_shoot
03-01-12, 22:12
I was working on my SBR today, and noticed something really odd. When using my laser bore sighter, you cant see it through my T1. Why is this? I aligned my Troys, then slapped on the micro, and there was nothing. Please explain this?
Thanks,
Brandon
The optical coating applied to aimpoints is part of what gives them their long battery life. The coating is engineered to reflect as much light as possible of a certain spectrum, which allows them to get a brighter visible dot reflected off of the front lens, with less energy output from the led. since aimpoint uses red LEDs, that spectrum their coating is attuned to is that red. the coating is most likely applied to both sides of the front lens since that would just be easier, therefore most/all of the red light from your laser , which is a very similar shade of red, is reflecting off of this coating and is therefore not passing through the optic.
This is the same reason why looking through some optics makes everything look blue, because it is reflecting more of the red spectrum.
I'm on a phone and can't edit but I wanted to add, this reflective coating technology is call a "band-pass" coating. Because it allows a certain band of light frequencies to pass through it, and a certain band is reflected.
bsmith_shoot
03-01-12, 22:57
Thats what I thought, well, close anyways. :D I figured it had something to do with the coating. Thanks my friend.
God bless,
Brandon
militarymoron
03-01-12, 23:08
i sight in my T-1 with a laser boresighter. i can clearly see the laser's dot through it.
bsmith_shoot
03-01-12, 23:10
i sight in my T-1 with a laser boresighter. i can clearly see the laser's dot through it.
Which one you got?
militarymoron
03-01-12, 23:14
it's a laserlyte brand boresighter. here's a question: with your laser boresighter turned on and pointed at a wall, and holding your T-1 in your hand and looking through it (not mounted to the gun), the laser dot disappears the moment you look through the T-1 at it?
bsmith_shoot
03-01-12, 23:17
it's a laserlyte brand boresighter. here's a question: with your laser boresighter turned on and pointed at a wall, and holding your T-1 in your hand and looking through it (not mounted to the gun), the laser dot disappears the moment you look through the T-1 at it?
Yep. I also mounted the t1 on my rifle, and zeroed the dot to my irons. Couldnt see the laser at all. The optic is good with my irons, but the laser wont show through it.
Heres a real kicker, mines a Laserlyte too.
Brandon
militarymoron
03-01-12, 23:21
that's weird. i just tested my T-1 and H-1 with two different red vis lasers (laserlyte and the vis laser on a DBAL) and i can see them clearly through it.
just to double check what you're saying - this happens when the T-1 is not mounted to the weapon as well?
bsmith_shoot
03-01-12, 23:23
Sure does man. Funny thing is, I sighted in an M2 with it and could see it perfectly.
militarymoron
03-01-12, 23:24
ya got me there, then. never seen that before.
that would be a bit disconcerting for me to discover as i adjust the vis laser on the DBAL to the T-1's red dot to zero it, so that the IR laser is also zero'd.
I found this review on a SightMark .223 Laser Bore Sight from amazon.com
I purchased this bore sight to help decrease the time spent to zero the red dot on my AR-15. The product seems to be a solid piece of equipment and is very cool. One problem, I can't see the laser while looking through my red dot. My target was placed at 100 yards and my red dot is a AimPoint Micro T-1. The only thing that I can think of is the anti-reflective coating that AimPoint applies to their sights is causing this issue. Fortunately for me I can bore sight without this product, however, thought it would be neat to try one out. So just an FYI for AimPoint owners, this is not the product for you.
I don't understand it.
The coating applied to higher end red dots is only reflects a very limited wavelength spectrum. It is possible that only some brands of laser could be blocked, while other brands with a slightly different spectrum get through. Also aimpoint has no doubt changed the coating formula once or twice over the ears so maybe only the newer or older coated units block the laser.
Its even possible that the color of the surface the laser is relecting off of could be changing it's wavelength enough to allow it to get past the coating.
If we're talking a Class 2 laser (we probably are -- red/vis-only, continuous-wave beam, below a certain power output threshold), and you're trying to use it at distances past 25m in daylight conditions, we can table talk of coatings.
If we're talking 100yd in daylight, like what the dimwit in the Amazon review above stated, it's too far. He's not seeing anything because there's nothing left to see.
Light diffuses light, so all the photons being belted out by the sun are smacking into the photons in the laser; think billiard balls (lol, I said "balls!").
Past 25m, the chances of there being enough photons of the beam bounced back and able to withstand a repeat photon-battering on the trip back and make it through to your optic nerve is about that of me being elected Pope -- theoretically possible, but unlikely enough that it's not worth more than a split-second's whimsical thought.
If the above, it ain't got a bloody thing to do with coatings. Using a laser on a 25m target is a 50m trip for the beam -- 25m down, 25m back. There isn't enough oomph in a Class 2 device, under most normal daylight conditions (even overcast) to be able to push much further than that.
If one wants to use a boresighter to distances like 100m or thereabouts, your best chance of success is morning or evening nautical twilight conditions (dark enough for the beam to not loose oomph, light enough for the shooter to see)(or, be inside, but it should still be a bit dim), and preferably target surface that will contrast with the beam well.
Actually your standard household laser is a <5mw class IIIA laser not II. Also, depending on the conditions and quality of the product it's perfectly possible to see a laser at 100 yards. I know I've done it it bright sunshine but only could see it off of steel panties red or white.
The OP said he sighted in his irons with the laser, so obviously he could see it before looking through the T1. Also, I believe he stated that he tried shining the laser on a wall near him and still couldn't see the laser. I'm pretty sure this is due to coating and not sunlight-based laser dispersal.
Painted not panties. That would be an odd shooting session.
Visible aiming lasers are Class 3R (same as 3a, they changed the designation a couple years back) -- CT, LaserLyte, PEQ-14, X400.
Boresighters are generally Class 2, and their beam divergence is usually not as tight because it doesn't need to be. LBS/PEM-1 springs immediately to mind....but yeah, if the boresighter he's got is a Class3R, that alters things somewhat. It bears mention.
I'm not denying that coatings are a potential culprit -- hence, why I typed "table," it could still be the case -- but in the absence of speciying laser brand/class and distance, it's not the first thing to be considered. Hopefully he comes back with that info.
I was going by the laser ute boresighter which Is class 3 but I see now that many cheap boresighters appear to be class 2.
But still, the fact that he can easily see it when not looking through the T1 and then suddenly it disappears when he does pretty much eliminates anything but optical reflection.
He said he was using the laserlyte boresighter, which is spec'd as a class 3a 5mw 650nm.
Painted not panties. That would be an odd shooting session.
Steel panties? Might make a fun novelty target. Who's got some spare AR500 steel...
bsmith_shoot
03-02-12, 19:37
Would the surrounding light make a differance? If its bright outside, or dark, would that make any differance in viewing the laser through the optic? It is a laserlyte, and the optic is a T1 2moa, and I can see it well through an M2.
Brandon
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