Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Teflon-coated bullets, colloquially known as cop killer bullets, are bullets that have been covered with a coating of Teflon to reduce barrel wear. Molybdenum disulfide is also sometimes used as a coating. In the 1960s, Paul Kopsch (an Ohio coroner), Daniel Turcos (a police sergeant), and Donald Ward (Kopsch's special investigator), began experimenting with special purpose handgun ammunition. Their objective was to develop a law enforcement round capable of improved penetration against hard targets, such as windshield glass and automobile doors. Conventional bullets, made primarily from lead, often become deformed and less effective after striking hard targets, especially when fired at handgun velocities. The inventors named their company "KTW," after their initials.