To learn Lester Flatt, Earl Scruggs & The Foggy Mountain Boys - (Original Soundtrack Plus Bonus Tracks) Bugle Call Rag chords, anchor your practice on these foundational sequence of chords - D, G, C and G. Start slow with ChordU's Free Tempo controller and increase your speed as you get comfortable. Configure the capo to your vocal range and chord preference, remembering the key of G Major.