Part of course:
All the details behind that 'Game of Thrones' insane dragon assault in 'The Loot Train Attack' (LATimes)
One of the more impressive shots from the battle wasn’t the CG dragon or even witnessing the scorpion — the giant dragon-slaying crossbow — in action thanks to Bronn (Jerome Flynn). It was when the Dothraki hordes descended upon the Lannister troops and, right before they clashed in hand-to-hand combat, the Dothraki stood up on their saddles to fluidly shoot arrows at their foes. Episode director Matt Shakman explained in the after-episode special that on set “horse master” Camilla Naprous wanted to bring something no one had ever seen before.