Dean Bowditch grabbed a hat-trick to hand Karl Robinson's side their first away win of the season, putting them into the play-off places.
Luke Chadwick rifled a cross in from the left and Bowditch slammed a no-nonsense finish past Bury goalkeeper Trevor Carson.
The Dons striker was denied a swift second by a super save from Carson, but punished Bury again after the break.
Carson denied both Ryan Lowe and Chadwick before Bowditch rifled home at the third time of asking and the striker completed his hat-trick with a cool finish after latching on to a clever free-kick from Stephen Gleeson.
Bury claimed a consolation when substitute Lenell John-Lewis lobbed the onrushing David Martin but Chadwick completed the rout in injury time.