I have the solution it's the complete ban on any semi-automatic firearm. Banned from being manufactured , banned from being personally owned. All semiautomatic firearms should be confiscated , destroyed and any criminal caught in procession of one should be incarcerated for a minimum sentence of 25 years period end of sentence.
It's a solution and it might just work , but what's the cost? First it's Unconstitutional , Second it will cause another Civil War , costing X amount of dollars ( maybe we can borrow more from China?) and XX amount of human lives but hey it will end " mass shootings " right? lol
Most gun murders are done with pistols IIRC it was like 87% there's your problem , obviously the problem is much more nuanced than that , drugs , gangs , poverty , etc
We live among killers , sociopaths , psychopaths , who can and will kill without remorse , sometimes they lash out and hurt people this has always happened and always will. You can't stop them , hopefully only minimize the damage they do.