To open it, you need to kill the past of any gunman, after which with a small chance you can meet a patron in a red cloak. He will not attack the character, but he himself can be accidentally killed. You need to kill all the enemies in the room without touching the bullet in the raincoat, after which he will leave. In one playthrough, you can meet several patrons in a raincoat. On later floors, the chance to meet them is higher. To open the Bullet, you need to save five.

Notes:
The bullet does not enter the Gungeon, but falls into it. The same thing happens with the Robot and the Shooter.

The Buyer is not happy at the sight of Bullet and looks at him with a reproachful look. This is due to his hatred of Pula for defeating and overthrowing Pushkar in the past.

Past Bosses Bullets are a reference to The Legend of Zelda: A Link to the Past.

Story:
Some time ago, Bullet was on his way to help Elder Bullet stop the evil wizard Aghanim from taking over the Gungeal. He discovered that the elder did not know how to use the "ancient weapon" - a wooden sword (original Blasphemy). The dying old man handed him the sword and Bullet went to stop Aghanim himself.

When he met Aghanim, he revealed his true plan - he was going to free Pushkar from captivity in order to enslave Weapons with his help. Bullet was able to defeat Aghanim, but the passage to Pushkar's dungeon was still open.

Once in Pushkar's dungeon, he immediately began a fight with Bullet. Unarmed, Bullet tried for a long time to defeat the evil king, but in the end emerged victorious. By thrusting his sword into Pushkar's head, Blasphemy took over all of his magic and turned into what it is now.

After his victory, Bullet celebrated by sitting on a tree stump, surrounded by the other inhabitants of Gungeon dancing and playing songs. What happened after that is still unknown.

The fact that Bullet, unlike the other Gunmen, didn't make any major choices hints that Bullet's past has come true in the present timeline.

Bullet Features:
The best starting weapon among gunsmiths. Also the only starting weapon capable of destroying enemy projectiles.

Immunity to contact damage and increased damage from rolls (15) due to the starting item Living Ammo.

Past Bosses:
Aghanim
Pushkar