From the times before the fall of the Castle. The blueprints are found inside the Armory of the Castle.
- Completing the Minutemen quest: Old Guns
- 1 Settler must man the Artillery Gun.
- Using an Artillery Smoke Grenade, the Sole Survivor can call in an artillery strike.
- 6 Defense
- Having artillery pieces in various settlements will let you call in a devastating attack on a large area from a safe distance. Just throw in the grenade and run back.