Surefire M951- Solarforce Compatibility Issue?

Hello,
Long time reader, first time poster.
Thanks to all for the knowledge I’ve gained through M4C.

So I bought this light a while back from a buddy that worked at a pawnshop and the pressure switch was/is toast.
After much reading I ordered a Solarforce L2 s6 tailcap from Ebay.
It arrived today and the test fit is no go.
After playing with it, it will screw on about 2 full turns and that’s it.
Is the light a Fake ? or my threads jipped up? on light or new tail cap ?

I’m going to try a friends tailcap from a real surefire and check fit.
It does light up if you jump from battery to light body.

Thanks for the help and the overall community!


You can see the first couple threads are more rounded, I think that’s for me trying it back and forth.

Surefire Left, Solarforce Right

I’m not familiar with that light model. I wonder if you wouldn’t need a scout style cap…??

From what I can tell its an older light. Its a P60 head and they way I read it 6P size parts should fit, but I don’t know.
Is the scout style cap a different thread pattern or will they fit a SF 6P style light ?
I’ve got to get with my friend that has a real surefire and test fit, seems he’s always working when I’ off.

I would wager it’s the tailcap. The Millenium series won’t take a Scout cap. The tailcap you have is a knock off of a Surefire UM00 tailcap.

The only thing strange looking is the cruddy engraving. It almost appears as if someone painted the light body and then stripped the paint leaving behind the remnants in the laser engraving that wouldn’t wipe clean given the porosity that results from the engraving.

Just a thought.

To my knowledge, no one makes a knockoff M-series body. They are difficult to machine. Most likely the tailcap is the issue.

Well gents the plot thickens.
Went to see my buddy after work and I believe his light is a G2, a rubbery looking 6P.

His tailcap fit my light.

My Surefire tapeswitch tailcap fit his light.

My Solarforce fit his light.

But the Solarforce will not fit my weaponlight
and I’m left wondering what my next move is.

Call the guy at http://brightflashlights.com/ and ask him if he has any of the UM00 tailcaps left for you to purchase.

I have the same light (M951) but I ordered it with a Malkoff drop-in. Pretty sure (99%) that I ordered it from brightflashlights. He put a Surefire clicker switch on it for me, the spring on the switch did have to be extended a tiny bit due to the Malkoff drop-in so it would engage the battery. Take a look at Surefire’s website and decide on the switch you want, then brightflashlights should have one to sell you. I have the switch that is slightly similar to the Z61 shown here (bought mine a few years ago): http://www.surefire.com/parts-accessories/switches.html The guy who runs brightflashlights is very knowledgeable and will get you squared away.

While you are at it I would highly recommend a Malkoff drop-in if you can spare the ~$40, amazing improvement… ~320 lumens vs 65 lumens. Good luck.

Much improved run time as well. I just recently sold a nice Surefire 951 setup with the UM00 tailcap and a Malkoff head. Hated to see it go but it’s just so damn heavy.

Update,

After much aggravation and not really wanting to put any more money in the light, I went to twisting.
After much turning and cutting we have a working light.
The only things I can figure is the light had trapezoidal threads and the cap has square cut ???
And/or the brass colored anodizing was to thick?
The original cap still fits with no play.

Either way its working now and its heavy as lead!
I guess its low tech recoil mitigation.
But for 30 bucks, 20 for the light and 10 for the cap, I’m happy.
I’ve looked at the Malkoff drop-ins and may eventually go that route,
and the brightflashlights guy will prob be the way to go next time.
Thank for the suggestions and help.