Let's get some stats, shall we?
Since 1982, in the US, about 1130 people have died from mass shootings.
American police in that same amount of time has killed over 38000 people.
The problem has never been AR-15s, or the lack of background checks, or anything of the sort. It's always been the pigs. But liberal suburbans enjoy the benefits of the pigs protecting their property while they kill poorer people, so telling them this makes them stare blankly, or they double down and continue to whine about weapons of war, to which I say: If you're so concerned with weapons of war being in the streets, why does every law banning AR-15s add exemptions to the police?