So I was told way back when this thread was opened, but the angle from which you have to hit it, is either broken or a myth. There was a video linked above but I believe it was
@Albert Winsford's video and is now private, but it was something along the lines of 5 marksman hits from me alone, not counting the others who were also shooting it.
It's a drone, it should prioritise not being seen as it should fall out of the sky with ease if shot in my opinion. Their pilots fly so obnoxiously low knowing the other way to take it down is head on collision with a heli (the only way I have ever seen one explode in over 5+ group attempts to take one down).
EDIT: It seems to have been removed off private,
@1A3-
https://medal.tv/games/gta-v/clips/KuDEezz-zcVXi/d13378DDe1s4?invite=cr-MSxJWjYsMzM3NzMzOTUs