The Heckler & Koch P7 is a compact semi-automatic pistol normally chambered in 9 x 19 mm Luger manufactured by the German company of Heckler & Koch.
It was designed beginning in 1971 to be compact and have enhanced safety features.
After several years of development, the first version of the P7, the PSP (Polizei Selbstlade-Pistole in German, or Police Selfloading Pistol), was released by HK in 1976 with mass production beginning in 1979. The P7 line ended its production run in 2005 with a limited production run in 2006.
The P7 was one of the pistols selected for the United States Army trials to find a new service pistol to replace the M1911; it was eliminated early in the competition for not meeting specifications. The Army eventually chose a version of the Beretta 92. Despite its high price, it has been fielded as a service sidearm by several American police departments including the New Jersey State Police, the Utah Highway Patrol and the United States Park Police
A unique feature of the P7 is its lever cocking mechanism. It is a Single Action pistol (i.e. one whose trigger only performs the sole function of releasing the hammer\striker, without performing any cocking action), and some consider it one of the safest pistols for carrying with a loaded chamber. This is because it is only cocked when the lever, conveniently located on the front of its grip, is squeezed. Releasing the grip decocks the gun, rendering it immediately safe. Although there have been several incidents of police officers losing custody of their P7 handguns during scuffles, Massad Ayoob asserts that there has never been a case of a so-disarmed officer being shot with his own weapon, due to the proprietary and not well-known nature of the "squeeze-cocker".
Another unusual feature is its gas-delayed blowback operation allows its barrel to be fixed to its frame, unlike most semi-automatic handguns. Propellant gases are vented from the barrel into a cylinder that delays the rearward motion of the slide. Other pistols that use this unusual system include the unsuccessful Steyr GB, the Vektor CP1, and the Norinco Model 77B. These pistols are very compact compared to other locked breech pistols, due to their fixed barrels. The fixed barrel design also results in a pistol that has a higher degree of intrinsic accuracy than most "locked-breech" designs.
Barrel axis is also very low, decreasing muzzle flip and "felt" recoil. The P7's firing pin can also be conveniently removed from the slide and replaced in seconds for safe storage.
A slight disadvantage that the P7 has for a service pistol is that its gas system causes the gun to heat rapidly. The heat is especially noticeable after firing several dozen rounds in quick succession. This is generally of little consequence for practical defensive usage, but can be an impediment when practicing. P7s made for the American market feature a plastic heat shield inside the upper portion of the trigger guard. Also after sustained use, the P7's gas system is prone to fouling and requires regular scraping of the gas cylinder in order to maintain reliability. However it has been proven by the German GSG-9, that the pistol can go thousands of rounds before it will stop functioning due to fouling of the gas piston.