With the metal ring removed from the Stardust, it becomes apparent why this carto gives a stiff draw on SOME batteries.
It's because some batteries have the the eGo cone threads higher up and this creates a seal against the base of the carto. The absolute fix for this is to grind away some of the eGo threads on the battery. Of course, this makes the battery unusable with a cone, but if one is committed to using the Stardust as I am, or doesn't care about using a cone, this WILL do the trick. Works if one is using a 510 to eGo adapter on a mod as well.
Might try slotting the eGo threads with a dremel since this may still allow for a cone.