Old Guns

Old Guns is a quest and achievement/trophy in Fallout 4.

Quick walkthrough

 * 1) Return to The Castle
 * 2) Speak to Ronnie Shaw at the Castle
 * 3) Gain access to the Castle's armory
 * 4) Talk to Ronnie Shaw
 * 5) Build and assign artillery at the Castle
 * 6) Talk to Ronnie Shaw
 * 7) Follow Ronnie Shaw
 * 8) Head to the target area
 * 9) (Optional) Keep the radio on and tuned to Radio Freedom
 * 10) Throw a Artillery smoke grenade into the target area
 * 11) Speak to Preston Garvey

Starting the quest
This quest can be received from Preston Garvey in Sanctuary at a certain point in the game. Alternatively, a few days after securing the castle, one will be approached and engaged in conversation by a woman named Ronnie Shaw, or by listening to Radio Freedom. She tells of the old Castle's untapped armory. After some dialogue, the Old Guns quest will begin, and Ronnie will lead to a large hydraulic steel door within the Castle, she will tell that this door is not accessible and the player character will need to find another way around. Ronnie then leads inside the Castle's halls into the old General's office where a hallway (now blocked by rubble) leads to the armory.

Lower tunnels
Shaw will ask to clear the rubble. Using the workshop, the Sole Survivor can clear said rubble and gain access to the lower tunnels leading to the armory. This is done simply by scrapping the rubble in workshop mode. Inside are a few rooms with general junk, and a shelf with ten cannonballs for the Broadsider. There are also some minor defenses--mines and a single level-dependent turret.

Do not get complacent--guarding the far entrance is a heavy sentry bot called Sarge, who will instantly attack. After defeating him, one can go into the room before the armory. Inside one will find a computer with the last generals, General McGann's, last entries and also his corpse. The Sole Survivor will then need to go through the door to the West Bastion.

West Bastion
Shaw will access a terminal that will open the armory. Inside is an array of plunder, including an Artillery schematic and some Artillery smoke grenades (inside a yellow ammo box container on the metal shelf), which are needed for the next part of the quest. After taking the schematic, it will add an Artillery piece to the workshop under a new Special category. Speak to Ronnie and she will ask to build the artillery piece. Place it (some pre-existing spots exist on the walls if preferred) and assign a settler to them. After doing this, speak to Ronnie again and she wants to test the new artillery.

Testing the Artillery Guns
Shaw asks to keep the Minuteman radio station, Radio Freedom, on (optional task) and to throw a grenade into the test site (shown on the compass, and with a quest marker). If having the radio station on, Ronnie will speak via it. Once approaching the test site, throw an artillery smoke grenade into the site and step back. After a few seconds the guns will fire and Ronnie will tell the test was a success. After this, speak to Preston Garvey and complete the quest.

Quest stages
Quest ID: Min03 Complete Stage: 1000

Bugs
Старые пушки