First, unlock the PBX Auto-Slug 4 Shotgun by securing the "Riscos Altos" region (left side of the map). You can then request it by airdrop at any time. You can also find this weapon in some military bases from weapon boxes. Press R1 to use the secondary fire mode, and destroy any vehicle with it to get the "Pinball Dreams" trophy. You can also request a vehicle by airdrop, if desired.