 Lead is also cheap, easy to obtain, easy to work, and melts at a low temperature, which results in comparatively easy fabrication of bullets.Poisonous bullets were a subject to an international agreement as early as the Strasbourg Agreement (1675).The St. Petersburg Declaration of 1868 prohibited the use of explosive projectiles weighing less than 400 grams.The reasoning was that they figured if bullets were more deadly there would be less suffering.