Firearms are what revolutionized the world of Grey sky. These new weapons changed warfare forever, knights in full plate were soon made redundant by superior firepower (although still today some mercenaries or adventurers still believe in the use of heavy armor). Unlike the crossbow, firearms are complicated to operate, they need to be reloaded using black powder and be maintained regularly. The problem of the mechanism jamming or faulty ammunition catching in the barrel is still problematic to modern gunmen.