I've just finished watching "Under the gun", a powerful and revelatory look at the whole gun culture in the US.
Its hard to fathom how readily available guns are in that country, that you can buy a high powered gun which can take down a plane, with often no background check whatsoever needed.
Why is it that people on the US terror watch-list can be banned from boarding a plane, but can get as many guns as they want with impunity?
Why is there no centralized database about prospective gun buyers?