it's like allowing 40% of passengers to board a plane without going through security. would we do this? >> what would you like to see happen? >> three things must change to make america a safer place from gun violence. number one, a national background check. number two, a ban on the assault weapons. and three, a capacity of no more than ten rounds on magazines. >> according to one study that focused on mass shootings, high capacity magazines were used in half of the incidents occurring in the u.s. in the last 30 years and shootings were significantly deadlier when assault weapons and high capacity magazines were used. i've heard the idea that limiting access to high capacity magazines would make a difference before. now it's time to put the theory to the test. >> that's a lot of bullets. >> it is, sir. on this table is a sampling of magazines. this particular set here is for the ar platform rifle.