As many as 25% of HRC voters in MS were Limbaugh Republicans

According to exit polls in Mississippi, 13% of all voters were Republicans. Seventy-Eight Percent of them voted for Hillary.  That means 10% of all Mississippi voters were Republican and voted for Hillary.  

78% of 13% equals 10%.  Granted not all are Limbaugh republicans, but you can take it to the bank that many are.  Thus, if 10% of all voters are Republicans who voted for Hillary.  If HRC wins 40% of the total vote that means a quarter of her supporters were Limbaugh Republicans.

Because of this effect Obama's win could be slightly blunted.  For this reason alone, I say thank god Pennsylvania is a closed primary.