Minecraft wiki entry for PC_Gamer_Demo, associated text: The amount of gunpowder in this chest is supposed to be randomly determined (anywhere from 1 - 88), but the random number generator that determines how much gunpowder is given is seeded with the same number (19) for each new world, thus meaning that it generates the same amount of gunpowder in the same positions each time. It is unknown whether this is a developer oversight, or intentional behavior.