I had a night firing exercise this past weekend and had a brand new SF 900 on my rifle. After about 15 rounds the light went dark. I had the 120 lumen bulb in and did not have my 225 bulb with me. When I got home I put the 225 bulb in and it worked so I guess the 120 bulb is bad. Has anyone else had problems with this light. I like it but I definetly need more than 15 rounds down range before a crap out. Luckey for me I had a SF 9 AN as a back-up and was able to continue the training.

Bulbs crap out.
If this happens, it usually happens within the first battery change.
So like you've found - use the light and firearm in training prior to deploying it for real.
It is not unheard of for the MN10 lamp to crap out like this. I've not heard it mentioned for quite some time though.

One would expect range time to be the ideal situation for your weapon/tools to crap out - gives you the chance to think "I'm not ready for this am I?!" without being shot at.

If it was only "luck" that meant you had a backup light then perhaps you'd rather not rely on luck next time? Or for real?
For example, you could carry an M3 in your gear - the lamps & bezels are interchangeable. An idea could be to get the M3T - since the bezels are interchangeable it would mean you could swap between them depending on whether you are shooting indoors or outdoors.

I would certainly contact your SureFire Dealer (or SureFire directly) and let them know and I'm sure they'll take care of you.

Al

I was lucky to have the extra high lumen light(140 lumen), as the other lights I had, a Insight Tech M-6 and SF handheld combat light did not have the ass to reach out 75 yards. Actually, the 120  and 140 lumen light was marginal for that distance and in the future I will have the 225 lumen light, or larger. Thank-you for your input and comments.

When I built out all of our Patrol Carbines several months back, I had two bulbs fail during my function checks. In my "vast" experience, if a bulb is going to go bad, it will do it in the first few minutes of operation. Otherwise it should last a long time.

While SF's warranty usually does NOT cover bulbs or batteries, and I didn't bother, having a big lot of spares, I imagine that, given their past track record of excellent customer service, that if you called SF and told them about your bulb failing, they will probably send you a replacement. I'll also toss out that I was irresponsible in NOT calling them when ours failed, because if they are having a QC issue with their new bulbs and nobody tells them, it will never get fixed. So, in a way, you can blame me. Sorry.

Heat up a filament (make it more malleable), suspend it between two posts and subject it to shock…wow it breaks.  Any imperfection is the filament is going to compound the situation.  As already mentioned, it usually happens at the being of the life of the lamp.

Shotguns are especially notorious for making this happen.  I went through a string of ten MN10 lamps at one time in a LM90 Module attached to a Bennelli M1 Super 90.  I finally decided not to use the lamp/module during training and rely on the lamp for my most likely scenario, a one time encounter with an individual at close range.  I figured I would have enough light for long enough to get the job done.

Not an idea situation, but better than no light at all.

No matter who makes it, in terms of a device that uses any electronics it will fail.  Therefore since you can, you need to carry two lights, extra lamp and batteries if you are putting you life out there.

With the MN10 lamp assembly the compatible handheld would be a SF M3.

Other reasons for failure could include:

1.  Bad batch of batteries (leakage, short circuit, catastrophic explosion failure)
2.  Low Batteries (left the thing on / intermittent activation in a gear bag)
3.  Light is hit with Frag or bullets in a fight
4.  Weapon is dropped and lands on the Light

Hence the reason we advocate the practice and use of a handheld flashlight in conjunction with your shoulder-fired weapon in a pinch (among other things).

Respectfully,

Ken J. Good
Strategos International

My M962 came with a bad MN10 [yellowish beam, and a visible black spot on the lamp]; called SF directly, and the sent me a replacement no questions asked....the only problem was that they sent an MN11.  I called them again, and they sent an MN10, again no questions asked.

I then called Calvin [BrightFlashlights] to buy an M3 for interchangeability, as well as an SC2 to carry spare batteries and a lamp for the pair.

My dealer, Mid America Arms in St. Louis , said no problem. He  will replace the bulb. Whew.