More than 1 million people have been blocked from buying a gun after failing federal background checks since 1998. But some reasons for denial are more common than others.This summer’s spate of mass shootings has raised questions about why people like John Houser and Dylann Roof were able to bu …

In the week since John Russell Houser allegedly shot and killed two people in Lafayette, Louisiana’s Grand Theatre, gun sales in the area have risen and concealed carry applications are “through the roof.” According to Lafayette-based The Advertiser, Barney’s Police Supplies indicates gun s …