I am not overfilling them
NOT

If you take ANY UNUSED cart it is the same fit, I tried. It is tighter than a used cart, but not like the older attys. And since I switched back to an older atty with an older cart, guess what, NO LEAKING.
See above
The "New" carts are not "Designed" for this atty, they are just not compressed by the older atty, which is a hair smaller. I am going to compress the tip of the new atty's just so I can use them. IF you do not want problems, I would NOT order these new atty's. JMHO
By the way I have 5ea 510 kits, 10 full PV's + 20 extra atty's, my fav PV

, so I feel I know how a 510 works. I ordered from Innovapor to test this NEW atty, NOT IMPRESSED
Burnie