I think it plays like this...
--We have Hillary as a probable nominee. Our base doesn't like her much but we don't want to kick her out and upset the Clintons as the other Bozo's are non-starters with the general electorate
---BUT to get our base out, gun control is a topic that will get them fired up....so lets bandaid a bad nominee by firing up our base with topics that get them rolling.
My surprise though is them not digging in and pulling out the Abortion debate. Abortion is the left's gun control clause. War on Women, etc. Maybe it just gets women fired up and that's not enough?
Interesting though, from what I've read both abortion and gun control are gradually losing favor among the public...maybe not the hard core leftist base but from the public in general.