Could have been great... - SureFire M640DF Scout Light Pro Dual Fuel LED Weapon Light

Good, but could have been great…

First, the good stuff. It is ruggedly built, super bright, easily mounted weapons light. Unlike some other lights out there, it has one setting—on/bright. This is actually a feature I appreciate in a weapons light. With some other lights (which I love) I can’t tell you how annoying it is when I am trying to turn it on or off, and I somehow trigger the strobe feature. Fine for a handheld tac light, but I don’t want that on my rifle—so I am actually very appreciative they didn’t try and cram more functions in there.

The light is definitely bright. While I don’t have access to a light meter to test it, I would guess it meets the spec recorded by Surefire. In actual use, the beam doesn’t feel any more “intense” than any other light (it’s not like you magically put the sun on the end of your weapon) but rather, the “hot spot” (the brightest point in the center of the beam) is simply huge. When comparing it to other lights in the family (the KM2-C--a 350 lumen light--on white light of course) the intensity looks the same to my eye, but the spread is MUCH larger, with a more consistent hot spot. The beam is basically one giant hot spot. This surprised me, as it is a very diffuse beam with no way to focus it—but after messing with it a bit, I have come to the conclusion it doesn’t need it, as I don’t know that adjusting it would make it any more or less serviceable—it gives a long throw, with a nice bright beam as is, and doesn’t need further refinement.
In short, it’s a good, rugged, bright light in a solid form factor.

Now, why it could have been great:

First, the flicker is still there. Stretching out the spring in the battery compartment seemed to help, but it was flicker-city out of the box until I adjusted it. Maybe it won’t be an issue long term, but still concerning as that seems to be the most frequent complaint about this light which indicates a design flaw. Maybe it was a one-time thing for me, but the frequency of this issue in reviews, and the fact I experienced it, still makes me wonder if it will come back at the worst possible time…

Second, although the Surefire Scout family of lights is a pretty cool concept—this particular light IS NOT compatible with any of the other bezels (some incorrect Q&A on the product page here). Although physically, the M640DF is the approximately the same size as the other Scout lights—IT IS NOT. The inner diameter of the body is slightly larger to accommodate the rechargeable battery (which similarly won’t fit in the other Scout lights), and the head itself has a wider thread pattern—meaning it won’t mate to any other body and vice versa (I own both flavors of the light).

For those of you who didn’t know—this family of lights is made to exchange bezels (the “head” of the light). I thought this was pretty neat, and was excited about using an IR head (which only does 350 lumens of white light), and switching it to brighter head when I don't need IR was appealing (much cheaper than buying a full “new” light, and not having to remove it from the rifle when I want to “exchange” was pretty cool). This bezel and body IS NOT COMPATIBLE with any of the other infrared/white light combos… It only works with the dual fuel bezels, which are only “white lights.” Adding to the frustration, is Surefire puts a cute little flyer in the box which shows this light, and all the other components which WON’T mate to this body… The lights are roughly the same size… I can’t imagine the engineering challenges were so significant that they couldn’t make a truly customizable system, with exchangeable bezels and bodies--they made all the tail caps work... (The KE2-DF, KFT-A-DFT, and DF2-A-DFT—the bezel included in this kit, are all white light heads, which you wouldn’t buy multiples of.)

At any rate—it's not a deal breaker for me, as I own both flavors of Surefire Scout, and I am not planning on returning either--may be that is why the designed it the way that they did, as they got more money out of me. BUT—like I said, these things are the difference between a “good” and a “great” light for me, and for this price—it really should be “GREAT” right?