Lamp options for Surefire M4 Devastator

fivemega

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I have this one G4 Xenon Bi-Pin Socket from tad. Will that work? But using 2X16650's I don't want a 6V bulb do I?
I don't know what kind 16650 you use but if they can power up 20W bulb with first click, then no problem. Keeppower works fine.
Using 2X16650's you want a 6V bulb to overdrive it by 7.2V for brighter and whiter beam.
 

ebuchner

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I have this one G4 Xenon Bi-Pin Socket from tad. Will that work?
Mostly yes. The Tad sockets accept WA G4 bulbs just fine. I had to add 2-3 shims to get the filament low enough for a perfect focus. The only problem I have with the Tad socket is that it can't handle very much current or heat. Running a 5761 in one for just a little bit practically scorched it and may have oxidized the internal contacts a bit. At the moment I'm running a WA1185 in mine, but only for very short bursts for fear of irrevocably cooking it.

Hence, I'm still on the hunt for a sturdier MN bi-pin socket
 

vicv

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I have this one G4 Xenon Bi-Pin Socket from tad. Will that work? But using 2X16650's I don't want a 6V bulb do I?
Yes, that socket will work. It depends on what 6v bulb. Some can handle the higher voltage. Some cannot if it is a 100 hour bulb or higher. It should be fine. The Philips 7388 is an excellent choice and can be found quite cheap. Also look here. Look for G4 and he has written in brackets what are the proper battery set ups
 

thermal guy

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Ok couple more questions here. If that Philips 7388 is putting out 450 Lumens at 6 volts any clue what it's doing with 2X16650's "7.2 volts "

And if this 6 volt bulb is ok to use with 2 lithiums why would it not be ok to use my mn16 with them
 

vicv

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Because an mn16 is a 6.6v bulb rated at 40H. The 7388 is a 6v bulb rated at 100H. So it can be harder driven. Really, it's just a more robust bulb. I'd say it's probably putting out 600-700L
 

thermal guy

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I had no idea the runtime on a bulb would matter that way. Thank you sir. I have a few on order so I can try out.
 

vicv

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I
I had no idea the runtime on a bulb would matter that way. Thank you sir. I have a few on order so I can try out.

It's not the runtime. Higher hour bulbs are at a lower state of intensity. Take your common incandescent household bulb. Those are generally rated at over 4000H. That's why they last so long, but are pretty low temp around 2700k. But that doesn't look very nice from a flashlight. We like a whiter output. Around 3200k. That means the filament is burning 500k hotter. So the tungsten vaporizes faster, which leads to lower life. When you increase the voltage beyond the specs, it pushes the bulb harder for more output and higher CCT, at the detriment of lifetime. Surefire tried to strike the best balance of color and life, and they did quite well. My bulbs have lasted a long time. But they're tactical use lights and aren't really meant to be used for hours on end.
 

thermal guy

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My 7388 finally came in and yep had to shim quite a bit to get a good focus. Looks way brighter then my mn61 but I'll have to wait till dark to see.

So ya the 7388 on 2x16650 is quite a bit brighter then my MN61 on primary cells! The fact I can get this horsepower out the front on rechargeables is fantastic. I do have to triple click my keeppowers to get her going but I can live with that. Thanks again guys.
 
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thermal guy

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Not really but as mentioned above, MN20 will be better choice if you want to use genuine Surefire bulbs.
I use 2x18650 in bored out M4 with bi pin socket and WA1111 bulb.
Does the M4 still have decent wall thickness after it gets bored?
 
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