U.S gun death has fallen, considerably since peaking in the mid 90s. But it still remains far higher than any other wealthy nation in the world. As does the rate of gun ownership. Mass shooting only make up a small of total U.S gun deaths. They occur with alarming frequency.
The issue resurfaced in June when a gunman singlehandedly killed 49. People in a gay nightclub in Orlando. That was marked the deadliest mass shooting in U.S history.
This is an issue that you need to address. That's deeper background checks for purchases of all guns. Also raise the price by 45% on all purchases.