The NBW (short for Nahbereichswaffe, meaning "close range weapon") was a prototype personal defence weapon or handgun designed by Heckler and Koch. It is sometimes erroneously referred to as the "G11 PDW" due to its association with the G11.
The NBW was one of the proposed weapons in the G11 series, along with an assault rifle (G11), a carbine (G11K2), a light machine gun (LMG11) and an unnamed 9mm caliber SMG. The NBW was proposed to be deployed as a side-arm, probably for vehicle crews. A new caseless cartridge caliber was also to be introduced for use with the weapon, the 4.73×25mm PDW. A mock-up was produced in the late 1980's, but before the G11 project could be finished, the Cold War ended and the funding for it disappeared, due to the reunification of Germany slashing the defense budgets. The NBW, and its ammunition, were both shelved, as well as the other G11 variants.
The NBW's mechanism would have had a gas-operated feed slide with a sliding chamber, an ejector, a rotary firing pin, and a cartridge stop. When a round is fired, the sliding chamber goes downward into a feeding position, as the cartridge stop holds a fresh round in a loading position as the feed slide then pushes it into the chamber. The cartridge stop acts to prevent jamming. Because of the caseless ammunition, there is no extraction cycle.
The NBW would have used a pistol-caliber variation of the G11's 4.73×33mm round, the 4.72×25mm PDW. While slightly smaller and is shorter in length, it has the same kind of construction; a solid block of high-ignition temperature propellant with the bullet telescoped inside of it. It would have fed into the weapon from a 20-round detachable box magazine.