Scooter Braun sounds like he's just about done trying to commandeer the Justin Bieber train (or trainwreck, depending on how you look at it).

The music phenom's longtime manager, speaking with GQ magazine's March issue, opens up about the struggle he's had trying to reign in the singer, whose cracks in the armor have ripped into huge holes in the new year, with a DUI arrest, an entourage full of headaches, and a pending felony investigation in another incident