I've learned from all this gun control or gun "safety" mess is that many federal level elected officials know that these anti-assault rifle & anti-extended firearm magazine laws are not really going to pass but they want a vote to show they did it.
That way when any parent or activist or media reporter asks them what they did about gun violence, they can honestly say; "hey, I voted for these new measures, but it just didnt go through."
Even POTUS Obama backed away from really strict laws and made it more about 1 vote(showing support for crime victims or their family members).
I say the ATF & other cops/prosecutors should enforce the gun laws they already have.