The Heckler & Koch P9S is a military and police pistol using an unusual breech locking system derived from the company’s highly successful G3 assault rifle.
The Heckler & Koch P9S has been adopted by German armed forces and police forces and has been widely sold throughout the world. Some have been manufactured in 7.65 mm Parabellum chambering and also in .45 ACP chambering for export to the United States, but the 9 mm Parabellum version is by far the most common.
The roller locking system for the breach relies on a two-part breech block which is held close by two small rollers which engage in recesses in the barrel extension. The rollers are carried on the forward, lightweight, portion of the block which is actually the part of the slide.
When the pistol is fired, the light portion, impelled by the pressure on the cartridge case, attempts to move backward, but the inertia of the slide keeps the rollers forced outwards and the block section locked to the barrel.
As the inward pressure on the rollers, due to the pressure on the forward section of the block, gradually overcomes the inertia of the slide, so the bullet speeds up the barrel and leaves, allowing chamber pressure to drop to safe levels before the rollers move in and the slide and breech block assembly are free to move.
The Heckler & Koch P9S pistol has an internal hammer, with a protruding indicator pin at the rear of the frame which extends when the hammer is cocked. There is a thumb-operated hammer release and re-cocking lever on the left side, allowing the hammer to be lowered under control on to a loaded chamber, or rapidly cocked from the ‘down’ position.
The barrel has a ‘polygonal bore’ in which the four grooves (6in .45 ACP caliber) are merged into the rest of the bore so that the final result resembles a flattened circle. The Heckler & Koch claim that this reduces friction and bullet deformation and promotes a somewhat higher velocity.
Two variant models exist: the Heckler & Koch P9, now discontinued, was the same pistol but with a conventional single-action lock; the Heckler & Koch P9S Sport Competition Model has a longer barrel with balanced weight, adjustable trigger stop, fine-adjustment rear sight, and an anatomical wooden grip.
The barrel is 5.5 in (140 mm) long, leading to a slight increase in muzzle velocity; with barrel counterweight fitted and a full magazine, it weighs 45.2 oz (1290 grams).
Technical specifications: Heckler & Koch P9S
|Manufacturer:||Heckler & Koch GmbH, D-7238 Oberndorf/Neckar, Germany|
|Type:||locked-breech double-action semi-automatic|
|Caliber:||9 mm Parabellum|
|Barrel:||4 inches (102 mm)|
|Weight (empty):||30.8 oz (875 gm) with empty magazine|