How Guns Work A gun is a weapon that uses the force of an explosive propellant to project a missile. Guns or firearms are classified by the diameter of the barrel opening. This is known as the calibre of the gun. Anything with a calibre up to and including .60 calibre(0.6 inches) is known as a firearm. The precise origin of the gun is unknown, although they were in use by the early 14th century and …showed first 75 words of 953 total…

…showed last 75 words of 953 total…the flight of the bullet, a technique called rifling can be used. Rifling is where the barrel of the gun and or the bullet is creased with spiral grooves that allow air to pass through. When the bullet is fired, the air passes through these curved grooves and spins the bullet. This spinning action allows the bullet to cut through the air more efficiently and fly on a more true course, thus stabilising its trajectory.