HK P7
The Heckler und Koch P7 is a 9 mm automatic pistol. Unusually for a pistol, it uses gas-delayed blowback as its operating principle. Propellant gases are vented from the barrel into a cylinder that delays the rearward motion of the slide. The only other pistol to use this system is the unsuccessful Steyr GB. The P7 is very compact for a 9 mm gun.
A unique feature of the P7 is its lever cocking mechanism. Although it is a single action pistol (i.e. one whose trigger only fires the gun, without performing any cocking action), it is one of the safest handguns in existence for carrying with a loaded chamber, as the gun is only cocked when squeezing its cocking lever, which is conveniently located on the front of its grip. Releasing the grip decocks the gun, rendering it immediately safe. Also, its gas-delayed blowback operation allows its barrel to be fixed to its frame, unlike most semiautomatic handguns. Its barrel axis is also very low, making the P7 one of the most accurate 9mm service pistols available anywhere. The P7's firing pin can be conveniently removed from the slide and replaced in seconds for safe storage.
The guns comes in several versions - the P7M8 with its eight round magazine is the slimmest and most concealable. The P7M13 has a 13 round capacity at the expense of increased bulk. The P7M10 variant is chambered for the .40 S&W round.
A slight disadvantage that the P7 has for a service pistol is that its gas system causes the gun to heat up rapidly, which is noticeable after firing several dozen rounds in quick succession. This is of little consequence for a police pistol, however.
The P7M8 weighs 780 grams empty, is 171mm long with a 105mm barrel.