Ok what you guys have been waiting for.
Manual exposure 1.2 sec shutter f/4 ISO 400 on all of these below
110Yds
K40
TN31
445Yds
K40
TN31
360Yds
K40
TN31
220Yds
K40
TN31
275Yds
K40
TN31
220Yds
K40
TN31
Looks to me like the TN31 wins…
I think so, too.
see your pics show how close they actually are.
Very close but IMHO the TN31 wins by a nose, what is the tailcap current on both flashlights? That might account for the slight variations in brightness
Any mouse over pics?
The little difference your seeing in the advantage of the TN31 is probably in my honest opinion coming from the deeper and slightly wider reflector. I would say that most of that advantage is coming in the extra length of the TN31 reflector vs the K40 reflector.
Mouseover K40 mouseout TN31
Nice beam shots and comparison! Thanks! Wow, with the mouseover, it is mighty close!!
Mouseover K40 mouseout TN31
Your probably looking at around 100,000 lux for the K40 and 110,000 lux for the TN31. Or it could be 10,000 less for each as well. But either way your probably seeing about a 10,000 lux difference
Selbuilt with his new calibrated light meter that not many actually have one by the way at least on these forums has said the TN31 to be 112,800 lux @1m. I would say that is probably just about spot on. But every sample may vary plus or minus a little. But he paid $75 to get his $200 light meter specific calibration tested and certified according to NIST standards.
Can you put your TK70 into the mix? My Supbeam K40 out-throws my 70 (pics to be gotten and uploaded when available)
In time, but not in this thread.
Mouse Over TN31
Wow….extremely close.
I’ll do this one for you even though I didn’t take the TK70 beam shot tonite. Mouseover TN31 mouseout TK70
Now this should lay to rest the TN31 or K40 out throwing the TK70.
I still like my TK70. 
Esp in 3 cell body shorty mode (with 2 x 32600s….a bit dangerous but i deal with that with SOPs)
Yea the TK70 is just one wicked plunger for those that want to call it a plunger. I call it one bad mojo of a flashlight.
Even if the TN31 had better throw I’d pick the TK70. Bigger hotspot, bigger spill.
The beam looks light is coming down at a different angle….