A rifle is a long-barrelled firearm designed for accurate shooting, with a barrel that has a helical pattern of grooves (rifling) cut into the bore wall. In keeping with their focus on accuracy, rifles are typically designed to be held with both hands and braced firmly against the shooter's shoulder via a buttstock for stability during shooting. Rifles are used extensively in warfare, self defense, law enforcement, hunting, and shooting sports.
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The term was originally rifled gun, with the verb rifle referring to the early modern machining process of creating groovings with cutting tools. By the 20th century, the weapon had become so common that the modern noun rifle is now often used for any long-shaped handheld ranged weapon designed for well-aimed discharge activated by a trigger (e.g., personnel halting and stimulation response rifle, which is actually a laser dazzler).
Like all typical firearms, a rifle's projectile (bullet) is propelled by the contained deflagration of a combustible propellant compound (originally black powder, later cordite, and now nitrocellulose), although other propulsive means such as compressed air are used in air rifles, which are popular for vermin control, small game hunting, competitive target shooting and casual sport shooting (plinking).
The distinct feature that separates a rifle from the earlier smoothbore long guns (e.g., arquebuses, muskets) is the rifling within its gun barrel. The raised areas of a barrel's rifling are called lands, which make contact with and exert torque on the projectile as it moves down the bore, imparting a spin around its longitudinal axis. When the projectile leaves the barrel, this spin persists and lends gyroscopic stability to the projectile due to conservation of angular momentum, preventing yawing and tumbling in flight. This allows the use of more elongated and aerodynamically-efficient bullets (as opposed to the spherical balls used in smoothbore muskets) and thus improves range and accuracy.