Some dimensions are the same. The OD at the bezel end is the same. It will take the same bezel, lens, reflector, but of course, the bodies are different, so there are different ID and thread measurements. Also the outer taper profile it different because of the smaller body as well, so, put the two next to each other and they do look different.
Thanks for the clarification. I am absolutely unfamiliar with maglites because they are to expensive here.
Would a par16 spotlight mod work for a c mag as well?
I do not know for sure, since the threaded area inside the head is so much smaller due to the C sized body.
Yes it does, I did it.
Check that $2.24 Triple emitter mag mod for pics
Sorry for the off topic, now I have found it…
Ain’t that the truth? :bigsmile:
Always good to see a C Mag mod. The 4C is ergonomically my favorite medium-large size light. I’m fond of the “pre-C” versions particularly because the head/body have quite a few (and tighter) threads, which eliminates any of that very slight wobble that a lot of newer C Mags have.
Mod on, OL!
Especially interested in the battery holder.
Well, there’s a couple more photos of it in the OP now.
Because of the price of copper, anything made with it now, becomes jewelery!
Subscribed, bookmarked and taking notes. 
I've been wondering about something while watching the mods that use high currents, and threads looking for ways to reduce resistance in the switch and replacing the switch with a higher rated one. Couldn't you just bypass the switch and hard wire batt- to the drivers ground? Especially in a mod like this where you're already using a master-slave configuration, couldn't you connect all three emitters to a slave, then strip the 7135's off the master? Then, you would only run enough current through the switch to power the master board, basically just the MCU. Or would the 3 slaves cause too much parasitic drain while the flashlight is off?
Anyway, the idea keeps rattling around in my head. If it won't work tell me so I can evict it and think about something useful. Or women. Or cookies. Something. 
Absolutely! It’s to the point where I don’t want to even use it any more. 3/4" pipe isn’t cheap. I ended up at Home Depot and bought a 2’ section for seven something and even the copper slip fittings are getting untouchable.
+1
Just can’t believe it’s not an MTG2 …
I’m probably not the one to answer. Are you saying no switch, or just using a switch in the control circuit, so that it only sees very low amperage? I use many of the DrJones programmed NANJG drivers where a momentary switch is used to fire the driver and yes, it does have parasitic drain. I believe that’s one of the problems with doing that style switch, like an SRK or Rook and others. There’s parasitic drain to contend with. I don’t worry about switches much until I get over 10 amps. The Judco switches work well for up to ten amps. I worry more about springs getting brittle from the current thru them.
Awesome, keep up the good work!
Tofty is building a 10A switch, Matt a 20A
He's wondering if hooking the 7135's up directly to the battery, with the MCU only being powered up through the switch, would cause parasitic drain. I've heard about 7135's leaking current when not even switched on, but the verdict seemed to go back and forth on that.
It's a very simple solution though that never crossed my mind :)
Yes, just using the switch to turn the MCU on/off, and leave the slave boards powered all the time bypassing the switch. The MCU would work exactly as in a single board driver with a mechanical switch. I don't see any downside other than finding room for an additional board, pending info on the slave boards' power use when the flashlight is off.
You also eliminate some resistance in the drive path.
Very cool. I like the battery holder/tray thing too. Will be tricky to make all the connections clean and isolated, but a very cool creation. Plus it’s parallel, so you can just pop in/out single cells if you’re in a pinch. Good luck with the new job post.
Battery holder is done. Photos in the OP. Now it's time for drivers.