In the general election, primary-crossover Dums vote Dum - ask McCain.
People who identify as D party vote straight ticket D more often than the analogous on the R side -- of course that's based on anecdotal evidence from FR during the past four election campaigns.
The anecdotal evidence includes all the FINOs who fought tooth and nail against McCain after he'd taken the nomination via the primaries and caucuses. In one case, the bashing continued for a couple of years (until that particular troll finally got nuked), and of course it also continues to this day in the form of accusations of all kinds.
Donald Trump has been drawing voters out of the D side, which apparently is just really evil now that he's doing it.
And McCain of course is against the Donald.