While equipping a fire bottle, you are still allowed to go into dead eye. Although the aiming reticule will be gone, it is still "present" during dead eye mode in the center of the screen. Therefore, you can still "paint" a cross on your enemies, assuming you have the reticule on any part of their body. Once marked, Marston will throw the fire bottle. When thrown, the fire bottle defies gravity and actually locks onto the enemy you selected and acts like a flaming homing missile. This is great for people speeding away on horses/carts. The bottle will keep flying until it hits the target and explodes on them.