Make Hope Great Again (Story Mission)
Return to Fort Drubman after recruiting Hurk to get this quest from Drubman the Elder.
He'll want you to pop down to the crossroads south of the FANG center, and eliminate everyone you see.
There are a ton of cultists there (which is sort of the point). The woods across the street (east) make for good sniping. Clear out the first batch of cultists, then occupy the ruins yourself. Trucks of reinforcements will start to roll up- this is a good time to start working on 'The Hurk Locker' achievement, by having Hurk RPG the incoming vechicles.
The next wave will be trucks and helicopters. Continue using Hurk, but you can can pitch in with the mounted gun out front(east) of the building.
You'll take out three helicopters before the cultists stop coming, and the mission completes.