Every MiniGun have two mode:
1 Human Control Mode : Survival can operate it by press E.
2 Self Control Mode : MiniGun shot visible infected by itself.
Change MiniGun Mode: mouse right button
Please use this plugins to spawn and move MiniGun :
[L4D2] 360° Movable MiniGun
l4d_ai_gun.cfg
l4d_ai_bullet_damage", "25", " bullet damage"
l4d_ai_attack_distance", "1500.0", ""
l4d_ai_attack_intervual", "0.1", "time between two shot
l4d_ai_attack_special_infected", "1", "1 enable, 0 disable"
l4d_ai_attack_common_infected", "1", "1 enable, 0 disable"