I have a theory. Perhaps this is classic Art of the Deal. He says something controversial and outrageous and gets 24/7 media coverage. Then, after a day or two, he will claim something like "what I was saying was that the Second Amendment people will vote against Hillary."
The result? He got a free opportunity all over the media to make his name synonymous with the Second Amendment, thereby appealing to voters as the gun candidate, and forcing Hillary to appear to be the anti-gun candidate.
Classic Art of the Deal. Say something outrageous, gets major coverage, articulate the comment, and dominate the media. Hillary won't be discussed for days.
It's actually brilliant when you think about it. Trump is controlling the conversation and tricking the media to give him free publicity. People reading and watching the news will now associate him with gun rights and Hillary with gun control.
After this blows over, he will have manipulated the media into giving him free advertising. He can say "I'm the pro-gun candidate" all he wants, but it is tactics like these that reach every American.
Pro-gun Americans won't care about what he said, and many moderates will be able to accept the comments when he inevitably clarifies them and insists that he was referring to votes and not murder. He successfully brought gun rights to the national conversation. He gets the added bonus of making the media look bad.
He will call the media liars, and accuse them of making it seem Iike he was talking about murder when he wasn't. It plays right into his narrative that the media is corrupt, incompetent, and untruthful.
The media will be giving him free publicity for weeks. They will think that they are hurting him, but even the most liberal sources will be helping Trump solidify himself in the minds of voters as the sole pro-Second Amendment candidate. Hillary will be irrelevant for a long time, and she will be forced into the role of the anti-gun candidate, more than she already is.