A 105mm projectile, the cartridge from the most common artillery piece used by the Americans, was often transformed by the Vietcong into a landmine. The primer (the part that ignites the main powder charge) was laboriously filed down and a small pad with a nail was placed over it. The entire cartridge was buried with the primer and nail pad facing up and covered with a thin layer of dirt or forest debris. The pressure of a foot would pierce the primer, ignite the shell, and result in a dead GI, or water buffalo, or Vietcong: mines are an equal-opportunity destroyer.