"(Harper) was loading his seven-barrelled gun, a weapon of extreme unorthodoxy. Each of the barrels was a half inch wide and all seven were fired by a single charge that punched out a spray of death."
— Sharpe's Company

Nock Gun, more commonly known as the Volley Gun, was a seven-barrelled flintlock rifle designed by James Wilson and made by Henry Nock of London in 1779. was capable of firing seven .50 calibre pistol balls simultaneously. It was originally intended for repelling boarding parties from Royal Navy ships.

The Nock Gun used in the Sharpe TV series

It The Royal Navy commissioned around 600 Volley Guns for crew usage, but some officers did not permit usage of the weapon on board their ships in fear that sparks released from the weapon upon firing would set fire to the rigging. Furthermore, few men were actually strong enough to fire the weapon, as the strong recoil of the gun could easily break a man's shoulder.

Sharpe first saw the weapon in use on the Royal Navy frigate Pucelle in Sharpe's Trafalgar. Upon first firing it himself, he thought he'd broken his shoulder. He used one again in Sharpe's Prey but thereafter contented himself with a Baker rifle.

During the Peninsula Campaign,  Patrick Harper wields the Volley Gun, having been given one as a gift from Sharpe who bought it from a Portuguese chandler. Harper used it throughout his time in the Peninsular War. Due to his massive build, he can fire the weapon without the recoil injuring him. His Volley Gun first appears in Sharpe's Gold and becomes Harper's signature weapon.

Hakeswill aims the Volley Gun at Sharpe.

In Sharpe's Company, Obadiah Hakeswill temporarily confiscates the weapon, and took it for himself, during his campaign to demoralize the Rifles. Hakeswill used the weapon later in the episode in an attempt to kill Sharpe amidst the confusion of a night battle, but he missed, killing a young ensign instead, although in the novel one of the pistol ball sized bullets hit Sharpe in the leg. Sharpe later takes the weapon from Hakeswill and, noticing that it was carelessly left loaded, threatens Hakeswill with it before giving it back to Harper.

In Sharpe's Battle, Harper uses the volley gun when Dona Juanita tries to kill Sharpe, and swept her out of her saddle in a bloody spray. The sound of the volley gun firing becomes a common occurrence in any battle in which Harper is involved.

Note: The Volley Gun seen in the Sharpe TV series was actually a reproduction model that was reduced in size, weight, and calibre by 30%. It was fully functional and apparently "a very powerful weapon".