All of what
@Chris K is correct. I have one too, and I started to hate it at first. Now I've tweaked it a little, it's one of my 4 favourite mods (I have a lot), used for days on end.
I've had to re glue the silver coloured spring plate a few times, but it's held since using a dab of thicker CA gel, but I'll probably use a thin smearing of contact adhesive if it comes off again. I nearly lost the spring hidden behind the top contact when I first fully stripped it for cleaning, not a problem now I'm aware of it.
The copper contacts do tarnish quickly, but I use a fibreglass brush to clean only the 3 actual points of contact every so often, and buff all the copper with a dremmel when I can be bothered. I'm now waiting on the silver contacts I ordered to arrive, which should reduce the need to buff.
I did fix the delrin base plug to the copper strip using contact adhesive, but have since re glued it to the mod using a couple of dabs of CA.
I don't really have a problem with batteries, I mainly use VCT5a's though. Some wraps may cause a problem, but I think that's mainly down to how much metal is exposed at each end. I have mine negative touching to top contact, positive down, and I did rewrap a couple that only had a small area of negative exposed. That part of the battery moves the most when firing. Every now and again it'll fail to fire on me, easily rectified by simply rotating the battery a little, nothing more. I also use the fibreglass brush to clean my battery contacts too. Something that I suspect gets overlooked sometimes.
I think the only niggle I still have is the 510, especially the locking part loosening. As said, overtightening can break the contact between mod and some attys. My workaround is to only tighten the contact ring when a atty is attached, just enough to stop the lock free spinning. The 510 can also be adjusted from the top with an allen key too. I did consider switching to a MM 510, but there is a size difference that would mean altering things too much. MM have now released a smaller 510 unit, so I may strip it and re measure it all later today.
I know this all sounds a pain, and this mod isn't for those who like an out of the box faff free mod. If you like a fiddle (ooh matron) this mod is really easy to fettle, and a joy in the hand. The parts are all accessible for maintenance, though not as readily so as box types like the Runt etc. It's different, curvy, tiny, inexpensive, now reliable, I bloody love it.
If you managed to read all this, well done. If you need any help, just give a shout.
