The Concert Across America to End Gun Violence Will Include 350 Events and over 1,000 Artists Nationwide on Sept. 25 Featuring Prominent Musicians such as Jackson Browne, Eddie Vedder, Rosanne Cash, Ryan Cabrera, Vy Higginsen's Gospel Choir of Harlem, Sam Harris, Kenny Loggins, Don Felder, the Gay Men's Choir of Los Angeles and Many More