Why do you need an amc7135 driver? Im sure the one it has puts more than 3A to the led.
I will come back with tests soon.
the pill is ridiculously small though..
The driver is 20mm as nekdo12 said. The contact area is 6mm around the pill.
The driver uses this controller and this mosfet. It doesnt run too hot.
Some decent wiring is used to the led.
Test with KK ICR @ 4.08v
HIGH: KK -> 3.495A -> driver -> 3.329A -> LED
-theo_mich
Better regulation, no strobe.
Nobody knows?
Here's an example of how I mounted a 17mm driver to a 26mm (I think) heatsink module. This is the 1.4A Nanjg AMC7135 driver.
It's messy, but works. I had a heck of a time soldering to that brass module! I used pieces of thin copper (cut off an old CPU heatsink) attached to the driver at opposite ends and soldered to the heatsink module. This particular module was filled with pieces of 4 AWG bare copper wire and solder to give the heatsink more mass (Chicago X's idea). I then added Fujik thermal compound between the driver and heatsink. If I could do it for a 26mm hole, you could do it for a 20mm one. probably just solder the edge of the driver to one side and use one piece of copper to bridge the other side (just be careful not to short anything).
-Garry
P.S. This is from my custom 3C Maglite which I should be posting a build post for eventually.
I've just changed a driver to 7135 V2 and XM-L U2.
I used old P6 brass pill that I did a few of my flashlights.
Now waiting for soldering and dry grease.
Old star XM-L with less grease.
Cut brass pill.
Waiting for soldering.
I just got mine today. It really came up in perfect condition. Well lubed, flawlessly working, well centered and throwy. I only had an old 18650 with me. It had an adapter with it and worked perfectly with a 18650. I found this really bright and as throwy as a Jetbeam BC40. Tailstands perfectly.
Thank you very much for the heads up. I'm glad I haven't paid for a Shadow J series.
Kokopelli, did you buy the M10 or tha M10a?
I am with you on the praise of the Keygos M10. I have two of them, and they perform flawlessly. 
In addition, they look good too. I am on the verge of getting a 3rd one. I used them on my bicycles. I have a pair of them on the bike I am on today. Also, I have a 18650 light on my helmet. Thinking about replacing it with another Keygos M10.
Just like you, I have been looking at the PRICES of the competing lights. This light is going for $23 with free shipping. IMO, one of the best deals out there in Flashligt Land!!
IMO again, this light is so good, it would still be a good deal at TWICE THE PRICE!!
I think I mentioned this before. They are all the same. I think they might put the "a" on there when they sell it with battery and charger.. Correct me if I am wrong.. But, I only see the specs for one Keygos M10..
As you all have seen in my previous posts, I have 2 Keygos M10s. They have been working perfectly. I have had them for about 2 to 3 weeks. About 2 days ago, I am riding, I have them mounted on my bicycle, and one of them stopped working. Okay, I figured a battery. When I got to work, I put in a fresh battery, still no work. Okay, I take it apart, put it back together, real tight, still no work. I switch tailcaps from the one that is working, still no work.
I take it apart again, check everything that my newbie eyes can check. Again, retighten the light, and it still doesn't work.
What am I up against here???
any one know if the c8 reflector fits the m10?
Good news.
Today I received another Keygos M10.
Driver is still 20mm, but these M10 have 17mm ring. No problem for driver swap
Take a pic of driver etc, do solder joints look intact, does emitter look OK? Battery deffo OK, check with meter? Clean all threads, tighten inside of tail cap… um not sure after that but try those and see what happens
This may help, different lights but maybe relevant, as posted by a guy on bikeradar:
My M10 had bad joints...spring in tailcap and front battery spring both broke in first day.
Does any one here have the C8 and the Keygos M10?
I have KD C8 OP and Keygos M10
how would you compare the c8 and m10?....any idea if the c8 reflector fits into the m10?
im quite happy with my m10.
Thanks Jeansy, I am all thumbs. However, true to the character and comradmanship of BLF members, another poster offered to check it out for me. I sent the M10 to them, and they did all what you stated above. It was one of those things you suggested to look for. I think solder points was the culpurt. Anyway, the member fixed it for me, kept it for another couple days to see if it would malfunction. It didn't, and now it is on its way back to me..
Great place and great people we have here! 
Thanks for the response and feedback,
ce
Sparky, your avatar has me cracking up laughing everytime I see it. I can't stop!! 