handwritten poster saying "take notes, chris brown." >> so that's why my daddy taught me early on in life how to use a shotgun. >> reporter: she then launched into her hit single "gunpowder and lead" about a woman preparing to shoot her abusive husband. ♪ ♪ gunpowder and lead ♪ >> reporter: a not exactly subtle reference to brown, who plead guilty to assaulting then girlfriend rihanna in 2009. >> miranda lambert, you remember, is a country music artist whose career is built on being outspoken, saying what she thinks. but in particular her songs are all about bashing no-good guys. >> reporter: lambert has been on a twitter tear ever since the grammys, where a wildly applauded brown performed twice and took home the award for best r&b album, tweeting "chris brown twice? i don't get it. he beat on a girl. not cool that we act like that didn't happen." in a tweet he's since taken down