Machine Gun Kelly’s headlining set at Louder Than Life festival in Louisville, Kentucky, on Saturday (September 25th) was certainly an eventful one. The rapper turned pop-punker was heckled throughout the gig, and at one point threw a punch at a fan who jumped the barricade to confront him. It’s safe to say that the fans turned on MGK due to his recent feud with Slipknot singer Corey Taylor. While Slipknot weren’t on the bill for Louder Than Life, a lot of bands on the Saturday lineup share fans with the masked metal act, including Disturbed, Volbeat, Code Orange, and more. Video footage shows Machine Gun Kelly performing to a chorus of boos, with festival goers flipping him the bird. At one point, when the singer made his way down to the photo pit, a couple of fans jumped the barricade to...