Bunker Buster

 is a quest in Fallout 76.

Synopsis
Out in the Mire sits an abandoned waste dump, concealing Sam Blackwell's bunker. The elusive senator's domicile contains many secrets, including a way to access the Whitespring Congressional Bunker. After all, he never returned the keycard after being forced into seclusion.

Walkthrough

 * This quest is a straightforward way to gain access to the Whitespring Congressional Bunker, though hardly an easy one. Blackwell's bunker is located near the northeastern corner of the map and requires passing through the Mire to reach it. The easiest way, using the Whitespring for reference, is to head northeast, past the National Isolated Radio Array and Sugar Grove, then skirting the southern edge of Harpers Ferry and going over the railroad bridge to the other side of the river. Then the player can jump down to ground level using the rocks, hug the cliffside and head directly north. The cave marker stands for the abandoned waste dump, which conceals Sam Blackwell's bunker.
 * To gain entry, the player has to find the bypass holotape, which is located in a pile of deathclaw refuse inside the outer cave (did we mention there's deathclaws patrolling the cave?), down the right-hand side when looking at the elevator to Blackwell's bunker. Then they have to play the holotape right next to the access panel in the elevator.
 * The keycard to the bunker is inside the senator's inner sanctum. To access it, the player has to locate the Security System Manual Reset note in the security room on the upper floor (to make the markers appear), then flip the breaker near the laundry machines, use the valve over the power generator, and finally activate the circuits in the vents above the kitchen. Doing so resets the security system. The player can simply use the handprint reader afterwards to gain access to the wrecked inner sanctum, turned up by Grey in search of Blackwell's congressional keycard. He failed where the player can succeed, using the combination 021584 (Judy's date of death) to unlock the painting near the cabinets to acquire the keycard.
 * The keycard is used on the reader next to the secure door. This unlocks the door and the quest completes once the player enters the corridor leading to the bunker entrance and hears MODUS.