OK. Yea, lots of options for next iteration.
Nope, the V5 threaded section isn't long enough.
View attachment 570981
So the shell needs threaded or a set screw. Maybe the current one could be extend through the shell? Would be a pain to line up though.
I think a hard insulator (Derlin or PEEK) is the easiest fix. Switching to a pre-made 510 looks more involved, especially for a spring loaded center pin.
But, with no easy way for Paul to make and test one, it won't be super quick.
May well require changes to the current 510 shell (open the center hole some).
Still, I think the current setup will be fine for most. As long as it's used AS INTENDED (ie with an o-ring under the atty to limit the pressure on the center pin). I get that some don't like the gap but it's not a functional issue.
If the gap really bothers someone, put a fender washer under the atty to extend to the same diameter as the atty. Like a trim ring when using a 510 tank on an Ego battery.Poof, no gap.