Reigning US Open champion Dustin Johnson fired a nine-under-par 63 Friday to match US compatriot Roberto Castro for the lead after the second round of the US PGA Tour BMW Championship. England's Paul Casey was third on 133, one stroke ahead of Americans J.B. Holmes and Chris Kirk, with another three strokes back to sixth-placed rivals Sergio Garcia of Spain and Americans Matt Kuchar, Kevin Na and Ryan Palmer. Johnson, who has found success after making a putter switch on the eve of the event, seeks his 12th PGA crown.
