Opinions on Surfire M951 weapon light

[BufordTJustice]

@Code7inoaktown

I’ve had quite a few of the DX drop-ins over the years and have given them away as gifts. The probem? High failure rate. I bought a batch of drop-ins two Xmas’s ago. Of those 5. Two have failed. Mind you, both were used in G2’s with the plastic head. And that was a different batch (Q5 emitters) so it’s a possibility that they have improved. Even on Surefire’s drop-in, they don’t recommend that you use it with a plastic head/bezel because it will degrade performance. On cheaper drop-ins without any thermal throttling, it just burns out the emitter. You will have the same issue with a weaponlight as the metal head has insulation in it to absorb shock for the incandescent. I recommend that you go with a quality drop-in like Malkoff or NeoFab’s D1000 or swap the head out.

Your best course of action on your funding is to also just run the stock incan lamp assembly. It’s “only” 60 lumens, but it is an incandescent which is more effective outdoors than most colder LED’s, especially in smoke, rain or foggy environments.

You stated the biggest concern for LED emitters: Heat.

Surefire G2 lights with the nitrolon head have zero ability to provide a heat-sink to the emitter. Even a top quality drop in will cook itself…or if temp regulated, it will throttle back to about 10% brightness until the heat dissipates (which it won’t).

I just packed the head of the light with thermally conductive grease. The heat is now efficiently moved away from the emitter into the head (and then into the air). If your LED light’s head doesn’t get warm after running for five minutes, it’s doomed to thermal failure. If it is a newer Q5 or R2 head (Much less a quad die setup), the head should get very warm in five minutes of running on high. If it only feels a little warm, there is no heat transfer and the emitter will fail…and I don’t care who makes it.

I’ve had these DX emitters work Quite well, I just use the el-cheapo thermal grease liberally.

For the G2 lights whose emitter’s failed, it;s why Malakoff recommends AGAINST their use in plastic head lights. The use of the 230 or 260 lumen Malakoff in an plastic head light will void their warranty if you try to exchange it. It’s not the fault of the LED emitter…it’s a faulty practice. It would be like installing spark plugs in your car without boot grease and wondering why you’re arcing after 10K miles. Every LED emitter must shed heat. That’s just the nature of LEDs, and it’s not the fault of the admittedly cheap Deal Extreme R2 emitter drop in.