They've tried to ban firearms for years. They're getting louder about eliminating the 2nd Amendment. They say they "respect the right to bear arms" and "No one wants to take your guns," but they are - unarguably - lying. That's exactly what they want.
So far, they've been stopped. If Hillary had won, there would have been a seismic shift in the Supreme Court, and civil rights like the 2A would have been gutted. Hillary lost, but that was only a bump in the gun control road. They never give up. Since they're having trouble limiting your access to weapons, they've decided to clamp down on your ability to purchase ammo.