After the war, the US military went to many ammo factories and took in some of the equipment used to make rounds. The US had tried for years to make casings out of steel which had they done so successfuly would have freed up brass for other things. They failed miserably. When they asked one of the engineers how they formed the cases without them splitting, the engineer replied "soap" we use soap to lubicate the casings before they go into the forming die