AC/DC drummer Phil Rudd pleaded guilty to charges of threatening to kill a former security guard and possession of cannabis and methamphetamine Tuesday in a New Zealand district court. The 60-year-old had previously pleaded not guilty to those charges. A second count of threatening to kill was dropped by police. Rudd's lawyer said he will challenge the conviction when Rudd reappears in court for sentencing on June 26. Police said Rudd ordered an associate to have his former security guard "taken out" last August.