guys just today when i played TDM in trenches as my new favourite(again) savage drone, i have achieved impossible....
DOM DOM DOOOOM!!!
i have gained a boomshot headshot blank, from the hip no aiming, just when i was going down from the nest marcus kept shooting me with lancer, i took out my boomer and shot him while walking, and HEADSHOT.
This is probably one of the impossibles like with the digger headshot