I often run into the issue where shoot the wing of the lead, and as he spirals down the pilot does not bail, so his drones just jump and bounce all over the sky, invulnerable until he bails or hits the ground, then they snap back into formation..
I often dont target the lead for this exact reason, but sometimes especially in a 30mm bird coming in from a high 3/9 at high speed, I tend to pepper the whole formation on the initial pass.