UCL lens and shock isolation in a shotgun mounted light?

I plan on getting an SureFire forend light for my Mossberg 500. I'm going to put my M60W-MCE into it, and I had a couple questions:

Can I use a UCL, or is that more prone to breakage than the stock pyrex lens?

Is there any advantage to replacing the stock aluminum bezel with a shock isolated bezel, or can the Malkoff take anything that a 12 gauge can dish out? If shock isolation will help, then is the the M2 head with Leef C-to-M adapter the best way to go, or is there a better solution?

Thanks!

Shock isolated bezels will hurt more than help with a well constructed LED module. They can cause intermittent contact and have poorer thermal performance than a normal bezel.

Not sure why a shock bezel is not recommended due to thermal performance. As I understand it, the Malkoff M60 thermal path is through the brass body, not the top rim or optic area. So the thermal contact with the M60 is to the flashlight body, specifically the "neck" area, not the bezel. The bezel can subsequently warm up because it is threaded to the flashlight body, but not because it has a direct thermal path to the M60. I don't think any drop-in has much thermal contact to any SureFire 6P family bezel (basically, only at the top rim of the reflector/bezel contact area), especially compared to the potential thermal contact to the flashlight neck. You can improve that thermal path by filling the gap between the M60 and neck with some aluminum foil.

Yep, but at the same time there is some conduction through the top rim between an aluminum lip in the bezel and the brass heatsink. The only reason to use a shock isolated bezel is reliability, with springless modules like the malkoffs they defeat that purpose. Shock isolated bezels have a tendency to not hold the module as tight as a stock bezel, so right there you have both intermittent electrical contact as well as less than ideal thermal properties.

Were this some cheap LED module it may help keep the electronics from being damaged, the malkoffs have fully epoxy potted electronics and from all reports are immune to weapon recoil and vibration. If someone has a shock bezel it can be made to work, not ideal but why throw money at something you can fix with a small wire loop. At the same time there's no need to buy something that will be a downgrade in this application. Use the foil trick though, it helps conduct heat away from the module and will keep the light working even if the bezel gets loose due to vibration.

Thanks for the responses! It seems like the regular aluminum bezel will be fine for my purposes... But after looking at the different weaponlights one more time, I'm confused again:

The incan weaponlight (which is abouut $80 cheaper) has a different head than the LED version. I was planning on buying the incan version and just swapping out the P60 with the M60W-MCE. Can I use the stock head on the incan version (which appears to have shock isolation) or do I need to swap it out for the aluminum (6P style) bezel of the LED models?

Here is the link to the incan version: http://www.surefire.com/623FA-Shotgun-Forend

And the link to the LED version: http://www.surefire.com/LED-Momentary-Constant-On-Switching-623LF

Yoda4561 said:

Yep, but at the same time there is some conduction through the top rim between an aluminum lip in the bezel and the brass heatsink. The only reason to use a shock isolated bezel is reliability, with springless modules like the malkoffs they defeat that purpose. Shock isolated bezels have a tendency to not hold the module as tight as a stock bezel, so right there you have both intermittent electrical contact as well as less than ideal thermal properties.

Were this some cheap LED module it may help keep the electronics from being damaged, the malkoffs have fully epoxy potted electronics and from all reports are immune to weapon recoil and vibration. If someone has a shock bezel it can be made to work, not ideal but why throw money at something you can fix with a small wire loop. At the same time there's no need to buy something that will be a downgrade in this application. Use the foil trick though, it helps conduct heat away from the module and will keep the light working even if the bezel gets loose due to vibration.

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I already noted that some drop-ins make minor thermal contact at the top rim of their reflector with the little shelf or lip inside of the SF bezel. Well, #1, that lip is anodized. #2, the surface area of that contact pales in comparison to what you could get between the drop-in body and the flashlight neck. #3, at least for my Malkoff M30, the white plastic that surrounds the optic is slightly higher than the brass rim, so there is no metal-metal contact anyway with a regular 6P bezel. There might be some metal-metal contact with a Z32 with the side of the Malkoff at the top rim. That's hard to tell. But, see #2.

On my C2 the diameter of the white optic holder is just smaller than the internal bezel lip, the brass body makes 100% contact around its diameter. This is identical to the fit in my nitrolon G2 head, and I'm betting the 6p is the same. Anodizing is not a signifigant thermal barrier due to its thinness, there exists an abundance of high quality heatsinks that are anodized. The important point here is that the shock isolated bezel in this application will introduce more problems than it will fix, which sort of defeats the purpose of using one.


** UCL lens. It's my understanding that borosilicate/pyrex glass is actually slightly less resistant to physical impact than normal glass. It's big advantage is the thermal stability so it doesn't crack when subjected to differences of hot and cold. I'm not sure if the glass used with the UCL's is actually tougher, but I'm willing to bet it's not signifigantly worse. I suggest sticking with the stock pyrex, I'm pretty sure their weaponslight lenses are already AR coated. Use whatever you want if you need to replace it.

Can't help you out with the weaponslight particulars as I've never used one, but I suggest making sure you know exactly what you need, I've heard of some surefire weaponslights having reversed polarity which work fine for incans, but don't work at all with LEDs. I think most folks just use a 6p and mount it to the barrel or on an accessory rail.

I never stated anything to the contrary about your point on potential intermittent electrical contact when using a shock bezel. I also agree that you can get some thermal pathway through the top edge/rim of a drop-in in contact with the raised lip inside an SF bezel. I maintain, however, that the surface area of that contact (and the quality of that contact -- the lip is not very smooth in my SF bezels) pales in comparison to the surface area that you could get if you used some foil to put the drop-in body in contact with the flashlight neck. And I also maintain that this is the designed thermal path for the Malkoff SF drop-ins, not some skinny little circumferential brass rim at the top of the module.

The SF shotgun fore-end lights I've seen use the standard battery polarity, including the ones for Mossberg 500s, Remington 870s, and Benelli M1S90s. Granted, I haven't seen all of SF's shotgun fore-ends. I think that polarity was reversed in the X200 weaponlight, which is an accessory rail light, not a shotgun fore-end light.

Thanks for the info on the lens strength... very helpful!

What I'm still confused on is why the incan models have a different (shock resistant) bezel than the LED models. In fact, if you buy the LED upgrade kit, it includes a 6P style bezel (to replace the shock-isolated bezel) and a P60L module. The P60L has the same design as the P60, including the spring and lack of thermal contact, so why the need for a different bezel?

If you're confused what I mean, just look at the pictures of the incan vs. LED models in the links above...

Presumably for the reasons mentioned above. The incan lights require the shock bezels to prevent the lamp filament from blowing under recoil. LED modules with potted electronics are virtually immune to those forces. The P60L has no real heatsinking mass and needs all the help it can get, as the only thermal paths it has are the mainspring>body, and the aluminum reflector>bezel. While the heat won't harm that module, it will make it dimmer as the thermal protection dims the light.

Yoda4561 said:

Presumably for the reasons mentioned above. The incan lights require the shock bezels to prevent the lamp filament from blowing under recoil. LED modules with potted electronics are virtually immune to those forces. The P60L has no real heatsinking mass and needs all the help it can get, as the only thermal paths it has are the mainspring>body, and the aluminum reflector>bezel. While the heat won't harm that module, it will make it dimmer as the thermal protection dims the light.

Click to expand...

Okay... then I guess my final question is this:

Can I safely use an M60W-MCE in the shock isolated bezel that comes with the incan lights (maybe with some aluminum foil) or do I need to swap it out for the 6P style bezel?

concept0 said:

Okay... then I guess my final question is this:

Can I safely use an M60W-MCE in the shock isolated bezel that comes with the incan lights (maybe with some aluminum foil) or do I need to swap it out for the 6P style bezel?

Click to expand...

I use an M60 in a shock isolated bezel on my AR-15 and it works fine (SureFire M951). It gets a bit toasty, but it works. You'll need the berylium ring. On my shotgun I just use a standard P60L. Works well enough, why bother? *shrugs*

Mercaptan said:

I use an M60 in a shock isolated bezel on my AR-15 and it works fine (SureFire M951). It gets a bit toasty, but it works. You'll need the berylium ring. On my shotgun I just use a standard P60L. Works well enough, why bother? *shrugs*

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When you say "it gets a bit toasty," are you referring to the bezel or just the M60 module? If the bezel is getting warm, that's a sign of good thermal transfer. But if the bezel is staying cool and the M60 module is getting warm, then that's no good.

I'm a bit concerned because the M60-MCE creates 2-3 times as much heat as the regular M60...

M60 will give you a semi hot bezel. It's just fine. The body will heat up but not to the point of damaging anything.

I've been thinking this over and while I first thought this module might be great for weapon duty I've since changed my mind.

" because the M60-MCE creates 2-3 times as much heat as the regular M60"
My thought as well. Gene's MC-E modules survive the heat because of good thermal transfer out of the light to your hand. If you have it running very long in what will basically be an unheld light I think it's gonna nuke before long.

Hopefully I am wrong but..............................$125 is a pricey experiment.

I'm pretty set on using the M60W-MCE in my Mossberg. But you're right, I really don't want to nuke my $125 module!

Is there a C-series bezel with extra fins/ribs for heat transfer? It doesn't have to be made by SF...

Solarforce make a semi ribbed version.

It benefits from swapping the stock glass with UCL, more light escapes and UCL is tough enough for the job.

http://www.lighthound.com/Solarforc...s-SureFire-and-GampP-Flashlights-_p_2811.html

I have a plain SS bezel ring that fits in there if you prefer the non crazy look!

I'm sure there are other options but this is the first to come to mind.

Sgt. LED said:

Solarforce make a semi ribbed version.

It benefits from swapping the stock glass with UCL, more light escapes and UCL is tough enough for the job.

http://www.lighthound.com/Solarforc...s-SureFire-and-GampP-Flashlights-_p_2811.html

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That looks like it might do the trick... I need to place a lighthound order soon, anyway.

I didn't see anything in the description about a UCL lens. Are you saying that I should swap the lens for a UCL or that it comes with a UCL?

It comes with a glass lens of some sort but I recommend swapping it with coated UCL from flashlightlens.com.

concept0 said:

When you say "it gets a bit toasty," are you referring to the bezel or just the M60 module? If the bezel is getting warm, that's a sign of good thermal transfer. But if the bezel is staying cool and the M60 module is getting warm, then that's no good.

I'm a bit concerned because the M60-MCE creates 2-3 times as much heat as the regular M60...

Click to expand...

The M951 body and bezel both heat up. Heat transfer does occur.

You might be able to find a better deal on than Solarforce bezel. Look around some just to be sure.