Would this be the type of adapter you're talking about? Stumbled across this several days ago, not understanding what it was for but saving the link just in case...
510/eGo to 510/eGo adapter - Vaping Me
Yep those are what I got; if you can get the ones without the hole in the center then better yet; with those I have to plug the holes with something; currently I just use tissue, but might try some silicone or some solder