For years, America has been well known for its gun violence, but last year, the statistics were off the scale. There has been a rise in shootings, but also a rise in the number of people going to buy guns. In the US, on average, there is a mass shooting every single day. But what in the last 12 months has driven people to buy and use firearms more than ever before? In this episode of the Sky News Daily podcast, host Noel Phillips speaks to Lucinda Roy, professor at Virginia Tech and former teacher of the man responsible for the killings in 2007; Kareem Shiya, co-founder of Open Source Defense - an online group, campaigning for gun rights, and Craig Jackson, Professor of occupational health psychology at Birmingham City University.