A firearm is a portable gun, being a barreled weapon that launches one or more projectiles often defined by the action of an explosive. The first firearms in the world were invented in 13th century China when the man portable fire lance (a bamboo or metal tube that could shoot ignited gunpowder) was combined with projectiles such as scrap metal, broken porcelain, or darts/arrows. The technology gradually spread through the rest of East Asia, South Asia, Middle East and then into Europe. In older firearms, the propellant was typically black powder, but modern firearms use smokeless powder or other propellants. Most modern firearms (with the notable exception of smoothbore firearms) have rifled barrels to impart spin to the projectile for improved flight stability.
Modern firearms are typically described by their bore diameter (75mm) or calibre (7.62mm) or gauge (12 ga.), the type of action employed (muzzle, breech, lever, bolt, revolver, semi-automatic, or automatic) together with the usual means of deportment (hand-held or mechanical mounting). They may be further distinguished by reference to the type of barrel used (rifled) and the barrel length (19 inch), the design's primary intended target (anti-aircraft), or the commonly accepted name for a particular variation (Gatling gun).
Firearms may sometimes be referred to as small arms when they are intended primarily for use by military forces if they can be carried by a single individual.
Firearms are aimed visually at their targets by hand using either iron sights or optical sights. The accurate range of pistols is generally limited to 50 metres (55 yd), while most rifles are accurate to 500 metres (550 yd) using iron sights, or longer ranges using optical sights. (Firearm rounds may be dangerous or lethal well beyond their accurate range; minimum distance for safety is much greater than specified range.) Some purpose-built sniper rifles are accurate to ranges of more than 2,000 metres (2,200 yd). A successful sniper attack has been made from slightly more than 1.75 mi (2.82 km).
The manufacture of firearms is a large industry. According to the National Shooting Sports Foundation (N.S.S.F.), a trade association for the US firearms industry, all economic activity from firearm manufacturing, distribution, and other ancillary activities totaled US$27.8 billion in 2010 in the United States.
In Firearms Puzzle 1.23