Since I had received a TN31 XM-L2 without AR coating on the lens, I decided to conduct an investigation to see if the AR coating truly helps bring out more lumens or not by comparing it with the original coated lens. Includes measurements on my PVC LMD.
http://www.youtube.com/embed/CsIukodVyTY
This is by no means a comprehensive vid on the topic since there are other variables (types of glass, coating, output level, etc.) but should give a general indication on its effectiveness.
Tim
I can’t see the video
Doesn’t work for me either.
Sorry about that guys, should be fixed now.
Informative video.
Definitely depends on the quality of the AR glass/coating. I remember when we did the BLF-X6-SE, an early sample AR lens actually had less lumens than a standard lens. The final lens did perform better.
It is!
thanks for the info. did you measure without any glass?
Thx guys and doh, sorry forgot to measure w/out the glass but I've done it in the past and that makes much more of a difference (I think on the order of >~5%). Indeed the type and quality of AR coatings make a huge difference. I think it's generally accepted that good ones can yield a gain of ~2-3%
Just looking at the cover to the video, it appears there is a lot more surface area around the head of the light to not reflect (in case of AR coated lens) light back down the light tube. There seems to be a whole lot of variables that causes much confusion. I tried to compare some uncoated to coated lenses using the same host in this thread. Overall, it AR coating seemed to make a difference, but I'm sure there is much I didn't consider in it.
I once built a Courui D01 for a thrower, was quite pleased with the 338Kcd I got from it. Then I got in the UCLp from flashlightlens.com. No other changes, just the lens swap, netted me 365Kcd. Needless to say, I was very happy with that $7 purchase. 
Yea, lenses from flashlightlens.com are real nice and the output increases have been confirmed. Definitely a worthwhile upgrade from the stock plastic mag lens…
I think my modified Olight Intimidator went from 610Kcd to 622Kcd. Then a change to the battery supply got me up to 645Kcd. That big 95mm UCLp is incredible! Invisible, gives the Illumination Machines Lum 5-90 reflector a clear view. 
Agree with other views, it largely depend on the quality of the coating if everything else being same.
I’ve only measured regular (cheap cheap) reflective glass vs no glass, huge difference, >10% in kcd drop in my T13, so your initial lens quality also counts when comparing vs AR.
I’m in the process of building another D01 for a friend, & have bought a few cheap camera filter lenses, which I’m planning on doing a back-to-back comparison for throw readings.
I should have it done tomorrow.
Over here also achieves improvements between 8% to 10% in kcds in my mods with AR multilayer glass lens regarding original lenses without any treatment
if you don’t mind me asking, what mods did you do to your Intimidator to get those levels of kcd? and what model was it? ( SR90, 92, 96, etc.
Thx for the informative follow ups. I have a feeling that the differences netted measured as lumens in my PVC LMD will be lower than measuring throw. Will do a beam throw comparo in the future and remember to include measurements without glass at all.
Again this was just a sample size of one so would be interesting to test additional samples in the future. Looks like a visit to flashlightlens.com is in my future. 
I would also like to know 
Well, the most annoying thing about AR coated glass lens is that the light gets kinda green tint after emitter dedoming, especialy if the emitter is 5700k and under
I had my Javelot default emitter replaced for that reason
Even without dedoming the LED.
That’s why I don’t like AR Coated lenses. I buy 4C or 3B XM-Ls because of the good tint - and then a lens destroys it 
Not for me… I preferably have a bit less lumens but a nice light color than the other way around.
Why not buy a LED that tends more toward red (something with “A” or “D” tint) for use in lights that use AR coated lenses? If you really don’t like the green tint, why are you buying green tinted emitters?