Calling all modders (Surefire M951 conversion)

Hello all. First time poster but long time lurker here. After looking around the forum a bit and gathering as much knowledge as I can comprehend, I've decided to upgrade my M951 Surefire to an LED. I've seen a lot of talk about the Malkoff drop in for this particular light, but the output attained from that drop in is a bit lower than I was hoping for.

I've recently ordered an EagleTac G25C2 equipped with the CREE XM-L U2 emitter because I was impressed with the output of this light (from paper specs, owner videos, and dealer review videos). I did some thinking and figured that if I used the same emitter and the same cell (EagleTac 3100mAh 18650 Protected) I should get the same output. Of course this goes beyond my current understanding of high powered LED flashlights but the fundamental idea seems simple enough: The only different components between the G25C2 and the M951 would be the housing and the tail switch, with one other caveat. I want the M951 to only operate on high (Max output for a single EagleTac 3100mAh 18650 Protected cell), I have no need for multiple modes on a weapon light. Considering there isn't much about the housing that would effect the operation other than the need to modify the collar to accommodate the drop in. The only mystery that remains is if the there is anything in the circuitry of the tailcap switch that would effect this setup.

As for pre-assembled Single mode XM-L U2 drop ins, here are the ones I have found.

http://www.lt-box.com/smo-cree-xm-l-u2-1300-lumen-3-18v-1-mode-led-drop-in.html

http://www.lightmalls.com/smo-cree-xm-l-u2-1300-lumen-3v-18v-1-mode-led-drop-in

I have no way of knowing the legitimacy of these units, they are just the only pre-assembled modules I could find. I'm definitely open to suggestions for more legitimate/trusted sources. Actually, I'm open to any advice regarding this project. Thanks in advance.

Welcome to CPF Grifter
Question does that Eagletac 18650 fit in your weaponlight body, because 18650s don't fit in mine, if so your lucky, Also realize an 18650 has a protection circuit in the end and that could be affected by recoil, its a real thin board with fragile components.
If you want HIGH power and can use rechargeables I'd suggest finding a dropin that can handle 2 AW IMR16340 cells (CR123A size and no battery protection circuit) that would be 8.4V max but will have 1/2 the capacity (550mah) of 2 CR123As (1300mah)
An XM-L at 3 amps will push a pair of CR123As real hard if they can sustain it for long at all.

I don't think those dropins you linked to will be the best. The LED in the pictures looks more like an XP-G for one thing not an XM-L
Things just don't come together between pictures and descriptions. The pictured driver is a 3.3-6v AMC7135 linear driver not bad for an XM-L at 2.8A drive current but thats not advertised.
I'd suggest you look into the custom modders here on CPF that make P60 drop-ins like nailbender or vinhnguyen54 - Custom Modified B/S/T Gene Malkoff is very highly respected with his own site malkoffdevices
They should work great and be much more dependable than a $15 budget light, do you really want a cheap drop-in in a weaponlight?
I've read that the LED dropins don't work as well in the shock isolated SF heads, as recoil won't affect a filament, heatsinking can be maximized by a solid fit, LU60 adaptor(P-series head to weaponlight) and Z44 head(6P style). Even SF sells their LED weaponlights with a Z44 instead of an M2 shock isolated head

Thank you for replying and for the very clear information. I do not have the EagleTac at the moment, but I already expected to have to bore the M951's body to accept the 18650 batteries. Also, I'm not too worried about the protection circuits of the batteries getting damaged from recoil seeing as this is only going on an AR15, I have no plans to mount this to shotgun or high powered rifle.

As for the drop ins I linked to, the price point wasn't the attracting force, it was simply the fact that I could not find any other prebuilt XM-L U2 modules listed. I have no problem paying more for a quality drop in so long as I get the output I'm looking for. I'll definitely look into swapping over to a Z44 head to replace the stock M2. To be completely honest, the only reason I'm looking to convert this M951 is because of the tail cap that has a clicky button and a receptacle for a remote tape switch (I like redundancies and usage options). If it will cost anything more than $70 to get what I want out of the M951 then I'll just sell it as it is (brand new and never mounted) and buy a different weapon light. I'd love some advice concerning that decision as well. Again thanks in advance for any input.

You might want to have a look at the Solarforce XML 1 mod edropin... I had one till I removed the driver to see under the hood...it si a simple one mode PWM driver.

http://www.solarforce-sales.com/product_detail.php?t=RB&s=40&id=193

kosPap said:

You might want to have a look at the Solarforce XML 1 mod edropin... I had one till I removed the driver to see under the hood...it si a simple one mode PWM driver.

http://www.solarforce-sales.com/product_detail.php?t=RB&s=40&id=193

Click to expand...

After machining out my 951 body for a redilast 3100-18650 cell, I bought this drop in. I had to do a bit of machining (center bore & hone) where the OEM dropin went and after that, am very happy with the outcome. Testing still needs to be done with my M4, but I can say that so far, im happy with the outcome.