There are no "loopholes".
“Our goal is to pass a bill that will close loopholes in the current background check process”
Schumer alluded to this a couple of weeks ago on one of the sunday shows with Cruz. He said that someone can buy a bunch of guns legally and be background checked at a gun show or in a store. But then that person can sell those guns privately without any background checks on the buyers.
And in saying this, Schumer gave away the game because he wants all guns to be registered like cars. He wants to the government to know who has guns and where they are. If a person sells guns privately, the government won’t know where they went and who has them.
And that’s the point! Because it is a danger to the public liberty to have the government know where the guns are because they will come and sieze them. It should not be forgotten that the reason the British went to Concord was to sieze the store of arms there so they could quash the rebellion.