The best part of Nashville’s Country Music Hall of Fame and Museum right now is probably an exhibit dedicated to the Bakersfield Sound, looking back on when artists like Merle Haggard and Buck Owens injected wiry electric Telecaster and old-time pedal steel sounds into the largely conservative country music landscape of the mid-Sixties. The exhibit includes Haggard’s signature sunburst Telecaster and the handwritten lyrics to songs like 1972’s racial anthem “Irma Jackson.” Most acts covered this extensively at the Hall of Fame have long hung up their instruments, but not Haggard. During a two-night stand at Nashville’s Ryman Auditorium that began Monday (“I’ll be here for two nights. You can stash your stuff in the same seat it’ll still be here”), Haggard proved he remains a master performer, storyteller and bandleader. He guided his seven-piece group the Strangers through both barroom and working-class anthems, soul and Western swing and the honky-tonk sounds of his youth with plenty of old-school showmanship. “I wrote a lot of these songs in my late twenties, and here I am singing them in my late forties,” Haggard joked. His real age? 77.