Before going straight to potting, the first step should be torture testing as-is.
I’ve had a s2 on a magnum 12 gage. 3.5" turkey shells are no joke.
I suspect the springs and cell are a more likely failure mode than the driver or emitter.
I put foam donuts around the springs to hopefully reduce cell oscillation.
It’s not guaranteed that potting would be a huge benefit.
in fact it started doing it to me only after I charged the battery
Something else that crossed my mind regarding driver potting and the recoil-tolerance of lights and why testing to failure should be first step…
It is my gut belief that the cell is a primary weak link. Its movement is inline with recoil, and is only mechanically impeded by springs, and wall friction. Wall friction is not really good for the cell, either, but that’s a side issue.
This is more than a gut belief, though, because a great engineering lesson came from the company “EOTech” a decade or so back. Oscillating cells were causing failures in a weapon mounted electronic device. Springs and connections were failing. They did design iterations and recalls. But in the end, their solution was to just mount the cell sideways, so that it was supported mechanically in the axis of movement.
Another thing to look at is cell mass. Inertia proportional to mass. Lights with high-mass 21700 cells use the same contact springs as CR123 cells. Proportional springs would introduce other problems – the weak link becomes cell terminals getting crushed upon installation. I’ve seen terminal damage on vented-flat-top 18650 cells when used on a shotgun. The components of the driver are of minimal mass, and generally soldered well. Maybe a big inductor toroid would be a problem if using a boost circuit.
An air bag is not guaranteed to save your life but its a good place to start.
Potting is a first line of defense againt failure from extreme vibration. There are countless other things that can go wrong.
True, and potting is generally a good thing for mechanically stressed components, but you don’t want an airbag to deploy when you back into a shopping cart, either.
You could just as well claim that mechanical isolation or cell size are first lines of defense, but all approaches require either redesign or other compromises.
I want to see a common failure mode to know which way to react, and have been so far unable to provoke a failure. Some serious testing probably could do what I can’t though.
light spot of S6 with B35AM is bad ,
pink T3 is in production
That’s too bad… I like the S6 look and feel. I thought the deeper reflector could also give it a bit more throw as well. Guess even an OP reflector still can’t fully resolve it?
i install OP for S6 B35AM, light spot is still bad ,
Which gasket specifically is needed to get better beam ln the m21h with sft40? Simon has a few options on his site?
The butterfly gasket works. It only raises the TIR height off the MCPCB though, and does not help centering. You could also use some other method to add space, like many layers of kaptan tape.
Darn it i just placed an order and assumed that was the one not to get so ordered the other two 5050 gaskets with different sized openings. Guess ill try next time. I dont have any of that tape laying around
Can anyone please tell what driver size is in the M21C?
Also, is there any difference between the M21D and the M21C-U?
Which 519A (stock, not dedomed) between 2700 and 4500k sold by Convoy are rosy or at least on the BBL?
I have yet to see a green 519a. I believe all are at least 0.00 DUV if not a little under.
@Simon_Mao Are they close to being available? Really interested in M21K.
Also any plans selling Molicel P28A or P30B? There are currently no high CDR 18650 in your store.
Can you offer a Tailswitch option for M21K? e.g. M21J tailswitch.
Simon, can you make a brass special edition L6? 
Yours are recently purchased from them?
AFAIK the main difference is the charging port in the M21D. The M21C-U uses a smaller diameter driver because it doesn’t need to fit the charging circuit.
I’ve fitted an Emisar D4v2 driver in an M21C-U and it was a drop-in swap.