I have tried 510's from 4 different vendors with every variation I can come up with. Half stuffed cart mods over stuffed cart mods 901 tips etc and the only conclusion I can come to is that they all leak. Seeing as how popular the 510 is and how rarely I hear anyone talk about this I can't help but wonder if I am doing something wrong. So how about it? Am I doomed carry a pocket full of napkins around when using a 510 or what?