http://www.fasttech.com/product/1234001
Looks great in the pics, unfortunately the one they're shipping is completely different.
CNQG was the original seller of the black SRK and I believe those were very good quality.
I'm not going to bother with Fasttech, since I'm never going to ship it back (costly) and since I have torn it down for modding, they can't really do much. I accepted it initially and tore it down. I should have inspected it better first.
I imagine I will pick it up again sometime and finish it, but I would probably have to center the led with the reflector, mark reflector and head for position and Nitecore the head on the body, so no one can twist it off That way it will look centered, even though it's not. That would mean loading batteries from the tail.
Time for that old song.... "Welcome To My World", Won't you come on in.... can't remember who sang that. But OH HOW TRUE!!! 
Dan.
OL you should make a charging jack and leave the batteries in there 
Hah! I was going to post the same then I saw you beat me to it.
That’s a bluesy song written by Winkler & Hathcock made famous by Jim Reeves in ’62 but I grew up on the Dean Martin version (only singer I know who sings from a sofa) :
RIGHT! I couldn't have told you though. I remember both of these guys singing the song now. THANKS!!! I needed that spot dusted off I guess! 
Dan.
Some seriously funny folks! Back in the day with Bob Hope and Johnny Carson when everything was shot live. They were always smoking and carrying a drink, on Television. Don’t see that anymore!
Bill Cosby, Flip Wilson and on other fronts Bill Murray, John Balushi, Chevy Chase, Gilda Radner, Harvey Korman and Tim Conway. Who’s world? Certainly a far different one than today!
Can’t believe I even remembered all those names! lol And there’s more, to be sure.
Thanks for the flashback, remember what a flashlight was back then? Oh Lord! But still better than nothing, or so we thought back then. Believe it or not, I have a pair of Eveready “D” cells, paper wrapped, from the 30’s that look to be in perfect condition. Wonder if they still have a charge? lol
OL, I’m stepping into your world a bit with a 3D NiMH Mag conversion. Had to get the Imedion Low Self Discharge cells and found they’re not exactly cheap, running as much and more as many 18650’s. Have an Elektrolumens drop in coming tomorrow with 3 XM-L2’s putting out some 2000 lumens on these cells. Can’t wait!
Best of luck figuring out how to drive this project, will be watching to see how you do it 
Belies our ages too. 
Dun forget the crooner old blue eyes Frank Sinatra of the rat pack and also Jerry Lewis who once teamed up with Dean for the funnies. They wouldn’t be the same with e-cigs today. Some singers nowadays just perform drunk. Looking forward to this SKR mod solution!
It was actually a 101 AK but I also did it with 8 x 7135 on a separate heat sink. The number of chips used is only relavent to the Vf at the drive current so the modded driver should be fine with a 6V led and 5x nimh.
Maybe I can get this thread back on track again... Maybe
I have uploaded photos of the solution to the loose head and now the reflector is as centered as it ever will be. The project is back on, but I will be waiting for a couple things to come in. See the last part of the OP for details.
WELL... I looked at the OP.... and AGAIN..... , you have outdone yourself! Modders work harder than us idiots that just build from stock!!! Your creativity is as always... AMAZING! You absolutely, positively affirm the saying that "Where There Is A Will, Threre Is A Way!" 
Thanks for sharing Justin!!... Most days in my shop I use one thing or another that I have learned from YOU...sometimes two or three!!!
Dan.
very cool!
Justin, if ever there was such, you’ll be inspiration for “Zen and the Art of Flashlight Maintenance”!
More photos have arrived in the OP. Working on the contact plates and tail cap mod.
Have you considered building a drop-out battery carrier? In this case with the shorter cells and loading it from the rear the front contact board would have to be a cloverleaf shape to clear the ID-shape of the stock tube, but the rear could be just plain round as it wouldn't need to pass through the flutes. With a single fatter-than-normal threaded standoff (I've seen it in 1/4" hex, would be plenty strong enough) thru the center to tie them together. That stuff is available in brass, so it could be soldered at the ends which would be more secure than a single screw with one central standoff.
Nice to see the build back on track!
Tail cap and contact plate assembly is now done. Photos in the OP show how to turn the SRK tail cap into a Nitecore Tail Cap.
You’ve had the old grey matter working overtime on this one. I dont think you would be happy if a mod just worked. Nicely done.