What I've done in a pinch is to remove the O-rings from the drip tip, wind some regular dental floss around the base where the O-rings go, put the O-rings back on. The dental floss helps to make the O-rings more snug until you can get bigger diameter ones.
From info on another forum, the base of the standard drip tip should be 13.5mm, so that may help. Another couple of options would be to try a different 510 drip tip with slightly larger O rings in the adapter or see if you can get a different adapter for it, as the adapter might be the culprit.
I'll take a look at some other options tomorrow. Just happened to see this before heading to bed.
