I 100% notice that my dual 14's are not collimated. It could be something else (mechanical alignment, shitty brain, idk many variables probably exist), but there's something off about these. I probably notice only because I've professionally used dual tube nvg's for years. I can also 100% handle the collimation error. It's a minor issue - but I can also handle a scope that's been mounted canted... I still try to fix it. That being said, I can fix a canted scope for free. Not so much my 14's it seems. My 2 cents on collimation.
Interesting about MX 10160. Those don't have adjustable gain, right? I'm guessing that's what is also in PVS15's then which makes sense as I understand that 31's have some proprietary tubes that allowed adjustable gain. I didn't realize the pvs15 had aviation tubes in them. Neat.
You probably have similar tolerance for optical misalignment as I do from the sound of it.
Like I said, brains are awesome, and they can adjust to a wide range of circumstances fairly automatically. Having used properly built binocular systems, it's also not surprising that it's noticeable, even if it doesn't significantly impede your ability to use them but it is something that separates properly built goggles from bridged 14s.
Yes, MX-10160s are ABC (automatic brightness control) only, no manual gain extension ("pigtail"). Most bino systems use MX-10160 "aviaition-style" tubes. The PVS-31s with their manual gain control use modified MX-11769 style tubes, L3Harris is understandably a little vague as to what the exact differences are, but I understand that they're related both to the manual gain extension, EMI shielding, and probably image shift compared to MX-11769s intended for monocular applications.
As for purging and DIY collimation, so again, "per the regs," if you disassemble the device at all, it should be re-purged. That's the "right" way to do it.
How much atmospheric ingress actually occurs simply by rotating eyepieces without removing them if any? Honestly don't know.
At the same time, there are guys that built their own units, some use canned air, some never bother to do anything, and especially in dry climates, report having no issues.
Again, this is kind of the same discussion, there's a right way and wrong way, and there's reasons that the right way is the right way--the choice is whether or not that applies to you and/or if it's important enough for you to worry about and/or do something about. If you're planning to stay relatively local with your NVDs, "cracking the seal" may not be that big of a deal. If you're doing a lot of traveling to different climates, elevations, temperatures, humidity levels, it might be more important.
This thread is probably worth a read if you want to consider it:
https://www.ar15.com/forums/Armory/DIY-Collimation-Technique/18-510765/ The other thread I mentioned is linked within this one.
~Augee
