John Dean "Jeff" Cooper (May 10, 1920 – September 25, 2006) was a United States Marine Corps officer and firearms instructor. He was the creator of the "modern technique" of handgun shooting, and an expert on the use and history of small arms.
Jeff Cooper was born in Los Angeles where he enrolled in the Junior Reserve Officers' Training Corps at Los Angeles High School. Cooper then enrolled at Stanford University, where he lettered in fencing, and he graduated from Stanford in 1941 with a bachelor's degree in political science. He received a regular commission in the United States Marine Corps (USMC) in September 1941. During World War II he served in the Pacific theater with the Marine Detachment aboard USS Pennsylvania. By the end of the war he had been promoted to major. He resigned his commission in 1949 but returned to active duty during the Korean War, where he claimed to be involved in irregular warfare in Southeast Asia, and was promoted to lieutenant colonel. After the Korean War he left active duty. In the mid-1960s he received a master's degree in history from the University of California, Riverside. From the late 1950s through the early 1970s he was a part-time high school and community college history teacher.
In 1976 Cooper founded the American Pistol Institute (API) in Paulden, Arizona (later the Gunsite Academy). Cooper began teaching pistol, shotgun and rifle classes to both law enforcement and military personnel, as well as civilians, and conducted on-site training for individuals and groups from around the world. He sold the firm in 1992 but continued living on the Paulden ranch. He was known for his advocacy of large-caliber handguns, especially the Colt 1911 and the .45 ACP cartridge.
Cooper, along with Michael Dixon and Thomas Dornaus, worked on the design of the Bren Ten pistol around the 10mm Auto, based on the Czech CZ 75 design. The cartridge was larger than 9×19mm Parabellum and faster than .45 ACP rounds.
The modern technique of the pistol
Cooper's modern technique defines pragmatic use of the pistol for personal protection. The modern technique emphasizes two-handed shooting using the Weaver stance, competing with and eventually supplanting the once-prevalent one-handed shooting style. The five elements of the modern technique are:
A large caliber pistol, preferably a semi-automatic
The compressed surprise trigger break
Firearm conditions of readiness
There are several conditions of readiness in which such a weapon can be carried. Cooper promulgated most of the following terms:
Clear and Safe: Slide locked to the rear, chamber empty, no magazine in the gun.
Condition 4: Chamber empty, no magazine in the gun, hammer down.
Condition 3: Chamber empty, full magazine in place, hammer down.
Condition 2: A round chambered, full magazine in place, hammer down.
Condition 1: A round chambered, full magazine in place, hammer cocked, safety on. Also referred to as "cocked and locked."
Condition 0: A round chambered, full magazine in place, hammer cocked, safety off.
Condition 0 is considered "ready to fire"; as a result, there is a risk of accidental or negligent discharge carrying in Condition 0.
Combat mindset and the Cooper color code