By Piya Sinha-Roy LOS ANGELES (Reuters) - American heavy metal rockers Avenged Sevenfold topped the Billboard 200 album chart on Wednesday, keeping off new entries by rappers Big Sean and Juicy J. "Hail to the King," the sixth studio record by Avenged Sevenfold, sold 159,000 copies in its first week, according to figures from Nielsen SoundScan. It is the band's second album to notch the No. 1 position on the weekly chart, which measures sales figures for albums across all genres. Avenged Sevenfold led four new entries in the top 10 this week. ...