I have a couple rda's that have extremely tight top caps. Most of them have two O-rings of which I usually remove one to remedy the problem. However, I do have a couple rda's that are still extremely tight even after the removal of one of the O-rings. At that point I remove the second o-ring. The removal of the second o ring usually makes the cap too loose and of course Leakey. Does anyone have suggestions? The caps on one RDA in particular is so tight that I am afraid to pull the cap because of the possibility of damaging the 510.