Who sings the theme song for the show terriers?

An extended version of the Terriers intro opening theme song, 'Gunfight Epiphany' by Rob Duncan. It was originally titled 'Steel Neena (Theme to Terriers)'. Watch Terriers on FX on Wednesdays at 10/9c. Created by Ted Griffin, Executive Producer Shawn Ryan, Starring Donal Logue and Michael Raymond-James.