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SureFire M600DF Dual Fuel Scout Light

5/15/19 - The M600DF Dual Fuel Scout Light from SureFire LLC is a compact and powerful LED weapon light that is powered by a single 18650 rechargeable battery or two CR123 batteries, capable of producing an impressive 1500 lumens and reaching out to 250m..

Description - The SureFire M600DF has been out about a year at the time of this writing, and is a compact but powerful scout light that comes with an 18650 rechargeable battery, but can use two CR123 batteries (hence the 'Dual Fuel' designation). A TIR (Total Internal Reflection) lens helps extend the throw of this LED light with an impressive hot spot and good peripheral beam, making it ideal for medium to longer range applications. It's available in Black or FDE (pictured here).

Key Features of the M600DF:

  • KE2-DF LED high-performance LED head with Iotal Internal Reflecion lens projects a large hot spot
  • Powered by either a single SF18650 rechargeable battery (included) or two CR123A batteries
  • Peak beam intensity - 16,000 candela (18650), 12,800 candela (CR123)
  • Max output - 1500 lumens (18650), 1200 lumens (CR123)
  • Max usable distance - 250m (18650), 220m (CR123)
  • Weight 5.15 oz w/battery
  • Length 4.45", bezel diameter 1.125"
  • M75 Mount - M1913 thumbscrew clamp (removable)
  • Z68 click on/off tailcap
  • Body material - aluminum
  • Finish - black or FDE Type III hard coat anodized

Included in the box:

  • M600DF Scout Light with M75 thumbscrew 1913 clamp mount
  • One SF18650A lithium-ion rechargeable battery
  • SF18650 charger (comes with wall plug and car charging plug)
  • User Manual
  • USB charging cable


What's in the box



The M600DF I received for this writeup came with a L18650-1SF Rev A rechargeable battery; I noticed that SureFire's website states that the M600DF comes with a later Rev B (SF18650B) battery that is micro-USB rechargable. The 18650A needs the included charger to charge the battery. The charger comes with a wall socket plug, as well as a 12V DC automobile socket plug. The charger will accommodate two batteries. Specs on the SF18650A battery are as follows:

  • Protected 18650 (internal projection/safety PCB)
  • Rated capacity 3400 mAh
  • Voltage 3.7 V
  • Charge voltage 4.2 V
  • Energy 12.58 Wh
  • Overcurrent discharge trip 6-8 A
  • Cycle life >500 cycles
  • Dimensions 18.55mm (diameter), 69.5mm length
  • Charger requirements: Use only a smart charger that uses a constant current/constant voltage charge cycle. Output of 4.2VDC, charge current of 0.5 to 2A

The M600DF's body has a 5mm larger diameter than the standard M600 to accomodate the larger diameter 18650 battery. CR123 batteries will move be slightly loose and move laterally inside the body, which isn't an issue. The contact inside the KE2-DF head is spring loaded and wide to ensure that the positive battery terminal is in full contact at all times. I've illustrated the M600DF below with the original M600 to show the difference in body diameter. The M600DF comes with a Z68 click on/click off tail cap which is standard on SureFire's 300 and 600 series lights. A slight press of the tailcap will activate the momentary-on while fully depressing the switch will activate constant-on. The Z68 tailcap can be 'locked out' for transportation, by turning it counter-clockwise until the light no longer activates. Accidental activation is unlikely, though, as the push button switch is recessed. The heads will not interchange, though, as the diameter of the threads on the M600DF and M600 are different.

18650 battery

Two CR123 vs one 18650

M600DF vs M600 size difference

Heads not compatible, but tailcaps are

Advertised output and run times are as follows (on full battery charge):

1500 lumens
16000 candela
1.5 hrs
Two CR123A
1200 lumens
12800 candela
1.25 hrs

All performance claims tested to ANSI/NEMA FL1-2009 standard on fully charged batteries.

Notes/Observations - SureFire's Scout lights have become one of the most popular weapon lights since I first featured them on this website in 2005. Back then, the KL4 head that came with the M600A put out 65 lumens. LED flashlight technology sure has come a long way since then. 1500 lumens seems like a lot of light, but it's not the only number that's important especially if you're outside and want to illuminate a target some distance away. I've never really had the issue of being 'blinded by too much light' indoors; even with the X300U pistol lights. As long as it's not accidentally activated on a white door right in front, the M600DF just lights up rooms and long hallways brilliantly.

Given that this light is capable of being used at longer distances, I tried it outdoors to test its throw using a couple of other lights I had on hand - my X300U-A with 600 lumens (I use the X300U on a couple of my rifles because of it's good throw. I don't have the 1000 lumen X300U-B) and the Olight M2R Warrior Flashlight which is rated at 1500 lumens as well. Throw is based on intensity (candela) while total light output is lumens. It's the intensity of the focused light at a given distance that determines how far it can illuminate an object. As expected, I found the intensity/throw of the M600DF to be superior to that of the 600 lumen X300U and the area of illlumination about four times larger since the diameter of the hot spot is about twice the size. It's bright, and lights up a large area. You can see the shape of the M600DF beam in the photo below - it has a very bright spot with good peripheral spill. It's not a tight focused beam, and not a flood either, but described as a 'beam with reach and surround light'; which is usable at close and far applications. I'd say that it's an accurate description of the beam.

Excited to try out the M600DF in different configurations, I tried to install the UE tailcaps from my older M300 and M600 Scout lights, but they wouldn't fit. They'd only screw on part way. Weird, since the Z68 tailcaps were interchangeable. I contacted SF's tech rep and they said that some of the older ones may not fit, but it's been a while, and sent out a current UE tailcap. I've illustrated the differences below between the two for reference. The older UE tailcap has some features inside that prevent it from being screwed down all the way on the M600DF body. Since few of my rifles have quad Picatinny rails any more, I tried the M600DF with some of Arisaka Defense's excellent Scout-compatible mounts. Even with the slight increase in body diameter, the M600DF could be used in all of the configurations that worked with the M600 body.

I did catch wind of some early battery-related issues of the DF shutting off intermittently from the constant-on mode, and tried leaving the DF on for 10-15 mins without shutting it off, to see if I'd encounter the same issue. It stayed on, and it also gave me a chance to see how hot the head got. It did get hot, but not enough to burn (even though there's a Caution warning on the head). The switch to the SF18650B battery might have been the in-line fix in response to the earlier battery issues. SureFire does not recommend using 18650's of any other brands in the DF.

Overall, I'm very impressed with the M600DF and the versatility it offers with it's 'dual fuel' feature. It's still compact enough to be considered a 'Scout' light, and is a great balance of size, weight and output.

Beam shape

Older UE tailcap does not fit

Newer vs older UE tailcaps

Thumbscrew clamp removed

Arisaka mount installed with current UE tail

Mounted to VIS-KM with UE tailcap

Mounted to SCAR16






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