Black Ops 3 beta set to take place 1-2 months before launch; expected to be 1-2 weeks
According to a video from Drift0r, the multiplayer beta for Call of Duty: Black Ops 3 is currently set to take place after Gamescom, 1-2 months before the November 6th launch date. In addition, according to a developer he talked too, the beta is currently set to last for 1-2 weeks.
The beta is for all players who preorder Call of Duty: Black Ops 3 on the PS4, Xbox One, and PC.