Pagan’s Wrath convoys are similar to Cargo Trucks, in that, they appear randomly around the map and are not static missions. They are a set of three enemy vehicles that are equipped with a very damaging machine gun on the back that drive around. They appear on the map as a skull icon and pretty much stay on the roads.
To destroy a convoy, all you have to do is kill all of the enemies (vehicles are optional), with one being a driver and another manning the gun on each vehicle. There’s a few ways to do this, with the easiest being explosive weaponry, like a RPG or grenade launcher. Another way is by planting C4 or mines on the road ahead of the convoy.
Either way, destroying two convoys will unlock the Stinger signature weapon in the store, while three will net you the Hand of Justice trophy/achievement .