If you produced a batch of 5mm springs I would definitely buy some. I don’t have a specific need right now, but it would be good to know that I had the best 5mm springs on hand for any build. 
@Barkuti, that is not actually the case. I did have initial problems when asking and “probing” a lot of manufacturers about the springs themselves, but once I found my current manufacturer, I did not have any of my problems.
They made my springs perfectly to my design requirements, the specifications of the real springs themselves were very close according to my simulations(mine did not take into consideration the contact resistance of the plating itself, and assumed a perfect weld), and thus, I am very happy with the 1st and 3rd Gen springs especially(the 2nd Gen spring designs were certainly not optimal :P).
Besides, I don’t recall Convoy using any BeCu alloy.
Currently, they are using a phosphor bronze alloy, which is good enough for most applications; my own springs are a step up from that, and are competitive with the Emisar BeCu C17500 short springs in regards to conductivity/mm length of wire(still worse, but not by much), with a good size, better mechanical properties, and lower prices(gold plating in small quantities is rather expensive as I’ve said before…).
Overall, I am satisfied with my current generation of springs, but I want MORE obviously from them:
better materials, better plating, better design, more of them, but I am limited by funds.
Still, thank you. I hadn’t even thought about CCS materials. I’ll look into it and perhaps do my usual math/simulations.
Thanks for answering, BlueSwordM.
I did a quick conductivity test on one of your springs long ago, injecting a high current over it with my precision power supply and measuring the voltage drop over its opposite ends as best as I could; I also tested one of the springs coming in one of the Convoy SST40 drivers, and couldn't find a significant difference. It was a quick test, and can't say if I did it with a gen2 or gen3 spring.
Your efforts are welcome in any case. Concerning the idea behind copper clad steel, or what I have in my mind, is some ≈70% O:) IACS, copper clad piano wire :-D spring with a decent plating. And of course, springs made with thick and short in lenght wire, for maximum conductivity.
I did that the other day and I got ~9mΩ for both small and large springs, Intl-outdoor about 4mΩ but they are significantly shorter, which makes sense because their lights don’t accommodate for protected cells, they also put a thin brass button under the spring to prevent the cell from crushing the components on the spring side of the driver.
@thefreeman, that sounds about right taking into account contact resistance.
I’m still not going to go with gold plating as I got a new quote, and the prices are still as expensive as ever, and I don’t want to increase the prices yet again unless I can massively increase the current performance of my springs.
My measurements don’t account for contact resistance, I used a four wires measurement with the voltage probes at the end of the first turn (bottom and top)
One can use these springs instead of doing a spring bypass? Results are the same or better ?
thx
A 1cm piece of 22AWG is only ~0.5mΩ, significantly lower than the measurements of the springs I posted just above (though it’s uncompressed, if the spires touch it could be lower)
Spring bypass is in general terms always better. However, and despite the above figure from the freeman is accurate (“1cm piece of 22AWG is only ~0.5mΩ”, 544.381µΩ or 0.544381mΩ according to Electrodoc software), it must also be noted that a proper spring bypass needs to be coiled, or else its life could be rather short. If the bypass is not coiled, it will elbow at some point due to the spring compression, and after repeated spring compression and release it will sooner or later crack at the elbow joint. For this reason the lenght of a proper spring bypass must also take coiling into account. It is only slightly more lenght versus straight wire, 30 - 40% maybe. Cylindrical toothpics make good molds for coiling the wire, by the way.
Properly coiled spring bypasses can last for ages (the solder points are critical and must be done properly).
Is there anyone else wanting springs again?
I’ve fixed all issues on my side, so shipping times should be back to normal and in tip top shape
Reminder that orders will be shipped on Friday, so if you want your springs to come as quickly as possible, Friday is the day 
Damn, looks like I’ll have to seriously upgrade my springs for Gen 4.
Simon now has a light that can sustainably draw 25A.
Not even my dual spring array can achieve that sustainably…
This is going to be especially difficult if I want to keep form factors…
Great! :-)
Silver or gold plated copper clad steel, please. O:)
And please, believe yourself attaining superb springs; with a really high IACS number and thick short prings, you can go much further than before.
“Thick and short” matters, as the lesser lenght in the spring wire means less voltage drop, while some extra thickness compensates for less spring coil turns while reducing voltage drop even more and increasing overall conductivity.
AWG14 coil diamerer maybe? :-D
@barkuti, gold plated is off of the table obviously.
Too expensive for the quantities I’m making.
Also, the problem of making them thick and short is that it restricts usability in many general lights.
Are the springs still available?
Sent PM.
Yes, and PM responded.
Great. And I responded to you. PP sent
BTW, Has anyone used these for the Mateminco MT07? It looks like the existing springs are bigger…
For those not in the know, the Mateminco MT07 is an MF01 Mini.
BTW, I’m still selling my springs
AND they are great springs…