Volley fire in the context of "Main battery"

Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, charcoal (which is mostly carbon), and potassium nitrate (saltpeter). The sulfur and charcoal act as fuels, while the saltpeter is an oxidizer. Gunpowder has been widely used as a propellant in firearms, artillery, rocketry, and pyrotechnics, including use as a blasting agent for explosives in quarrying, mining, building pipelines, tunnels, and roads.

Gunpowder is classified as a low explosive because of its relatively slow decomposition rate, low ignition temperature and consequently low brisance (breaking/shattering). Low explosives deflagrate—burning at subsonic speeds—whereas high explosives detonate, producing a supersonic shockwave. Ignition of gunpowder packed behind a projectile generates enough pressure to force the shot from the muzzle at high speed, but usually not enough force to rupture the gun barrel. It thus makes a good propellant but is less suitable for shattering rock or fortifications with its low-yield explosive power. Nonetheless, it was widely used to fill fused artillery shells (and used in mining and civil engineering projects) until the second half of the 19th century, when the first high explosives were put into use.

A ship of the line was a type of naval warship constructed during the Age of Sail from the 17th century to the mid-19th century. The ship of the line was designed for the naval tactic known as the line of battle, which involved the two columns of opposing warships manoeuvering to volley fire with the cannons along their broadsides. In conflicts where opposing ships were both able to fire from their broadsides, the faction with more cannons firing – and therefore more firepower – typically had an advantage.

From the end of the 1840s, the introduction of steam power brought less dependence on the wind in battle and led to the construction of screw-driven wooden-hulled ships of the line; a number of purely sail-powered ships were converted to this propulsion mechanism. However, the rise of the ironclad frigate, starting in 1859, made steam-assisted ships of the line obsolete. The ironclad warship was predecessor to the 20th-century battleship, whose very designation is itself a contraction of the phrase "ship of the line of battle" or, more colloquially, "battleship of the line".

A volley sight is a form of sight fitted to some military rifles at the end of the 19th century. They were used for long-range volley fire; massed-fire, usually defensive, from a group of riflemen. Separate volley sights lasted in service for around 30 years.