As a kid in New Zealand, Jack Salt can recall being aware of news reports of the frequent incidents of mass shootings and gun violence in the United States. It wasn’t until Salt, now a fifth-year senior basketball player at the University of Virginia, came to this country for college that he truly grasped the breadth of the problem. “You’d hear about it on the news when I was back in New Zealand, but just coming over here and just seeing, monthly, something so sad, it’s pretty tough to see that go on,” Salt said Friday after UVA’s loss to Florida State in the ACC tournament semifinals. “And to...