If I am not mistake they played on the latest installment of Metallica's Orion festival.
Actually I believe the vocalist appeared alongside Hetfield and Trujillo in a press conference for the festival. Although Battlecross' music hasn't yet grabbed me much I thought it was a very cool move for Metallica to bring out a lesser known metal band. I think they could play their hand at bringing over more obscure metal bands on the Orion festival.
Last year they brought out Ghost - thought that was cool and it did boost the band's profile a bit especially as Hetfield stated to the press he was a big fan of their music.