No, 10440's would be far overdriven with this light. Don't risk a potential explosion. Wait for the 14500's. Are you happy with the light outdoors or do you want me to tell you how to attempt to mod it?
I tried moving the reflector up a little with little pieces of paper for padding and that seemed to help a tiny bit. I can still see the yellow tint in the hotspot. Outside I can't really see it. There's only little threading at the head so I can't move the reflector out as much as I would want it to.
Ok, what's your tip for modding it?
If the donut is VERY pronounced, you can unscrew the crenulated bezel (although I haven't tried yet on mine). If you can remove the bezel and reflector, there should be a sticky round thin donut shaped tape looking piece that sits on top of the emitter board. It has a hole in the center for the LED to poke through. Use a dental pic or toothpick to remove that sticky round tape insulator. Once that’s removed, look at the solder where the + and - wires attach to the PCB. In most XP-G lights, if those solder blobs are sticking up even slightly, they will push on the reflector and force it away from the emitter, thus increasing the distance from the emitter to the reflector. If that happens, your beam might be out of focus and the emitter will be blocked by a portion of the reflector... so it wont be as bright as it should be. XP-G's generally like to be out into the reflector, not countersunk like XR-E's or shielded by it. So if you have those lumps of solder sticking up, you can reflow them with a hot soldering iron using a medium-quick swipe technique. You can also carefully sand, file or dremel the solder down for a lower profile. Ignition files work well. Hope that made sense.
I will add that if the reflector is already bottomed out on the PCB, you can also get a donut hole and may need to shim the other way - but that can kill lumens. It sounds like you may have already done that. In my experimentation, I've found that most non-pronounced donut hole XP-G's have larger hotspots that provide superior wide beam performance outdoors. This output performance seems to diminish when the hotspot is completely eliminated, because to do this, the beam usually has to be more tightly focused by moving it deeper into the reflector. This often narrows the hotspot and blocks a portion of the emitter behind the reflector. If I need to countersink an emitter behind a reflector or flush with it, I'll use an XR-E, not XP-G.
Another thought, does your reflector look well formed and correct for the light? Hows the fit?
Thanks FlashPilot but that sounds like a lot of work! I'm pretty bad with a soldering iron so I'm not even going to attempt it. Everything looks like it's in the correct place (reflector correct for light and fits nicely). It's the reflector's problem I think. As a test, I took the drop-in and put it in my Solarforce body with the bigger OP reflector and the beam is perfect. No donuts or yellow discolorations. Somehow that small smooth reflector in the R5-A3 is causing the problem. I have the same problem with my Trustfire F23. I don't think I can trust Trustfire lights anymore.
Don and Mr. Admin, you guys have this light right? Does your light have yellow discolorations/donuts in the hotspot?
I'm not sure. Once it's dark I'll try with a light meter across the beam - the hotspot is a bit too bright to look at close-up. It does seem to have a yellowish edge to the hotspot.
You don't have to look at it close-up. It's clearly visible about 3-4 feet away, more so in low mode.
Not in mine, it isn't. There might be a slightly darker ring around the hotspot but nothing as dramatic as you talk about.
I guess I'm just unlucky with Trustfire lights :(
Not as unlucky as I have been with DX throwers. See my comments on the HS-802 thrower. Or the Piritlight SG-L8. I have yet to receive a working thrower from DX. It shows a triumph of hope over experience.
Do you know if there's anywhere that sells OP reflectors that could fit into the R5-A3, or even the F23? I checked DX and KD and they don't seem to have one that small.
You should get the MXDL SA-28 as a thrower!
Hairspray. Reflector. Apply.
Don't need any more throwers since I got the Varapower.
Hairspray?
Just take the reflector out and very lightly spray with hairspray - it is a good idea to let it dry before putting it to use, the stuff is inflammable. You could very lightly spray with clear lacquer but it's much less reversible - you can wash off hairspray with acetone or ethyl acetate. That's probably the easiest way to "roughen" the reflector.
I read it on a photography forum - a cheap way of creating a softening photo-filter by putting hairspray on a UV-filter.
But they suggested a more controllable way to do it - create a "cloud" of hairspray, then move the element through it. Three or four passes should be enough.
WOW! It worked! I was skeptical but I can't believe it now. Hairspray is great! Fixed my beam. Thanks a bunch Don!
I applied the hairspray technique to the Trustfire F23 and now the beam looks great!! I have a bunch of lights now and all are OP 
I guess smooth reflectors are not my thing.
the draw on low on my new one from DX is only .17 amps! perfect for low usage, havent tried run time yet tho
high is drawing 1.7 amps (these numbers are from a trustfire flame 14500)
that seems a bit high for a r5, but im pretty sure its regulator loss
havent played too much yet, but this flashlight was meant to be a gift. may be buying myself one!
my review so far?
button is small and a bit tuff to press
amazing amount of light and AMAZING beam! great throw and decent flood. even contour between flood and throw parts
excellent build quality. expected it to be cheaper than this!!!
low is super usable (against what OP said) only .17 amps (tops) from a freshly charged 14500
VERY light whine from low, no whine from strobe nor high.
still very bright on a AA
2.15 amps high, .27 amps low off 1.5V duracell alkaline!
not as bright as the 14500, but outshines a MCU-C7 q5 with a 16340
one of the best constructed flashlights ive seen for under 20 bux. the best carry on ive seen yet. most people DONT like strobe, but as ive stated, it comes in handy when it comes to traffic
(ie spotting for trucks backing in, or stopped on the side of road etc etc)
Hey, that's an improvement! Would you be so kind as to do a low mode runtime test with a NiMH or Alkaline? Thanks!
I guess no hairspray for you.
Yup, he's not exaggerating about the beautiful beam of the R5-A3. It's just a big huge, smooth blotch of incredibly bright, warm colored light.