Gun

A gun is a tube that discharges projectiles that may be solid, liquid, or gas. A gun is typically a weapon which fires solid projectiles at a high velocity. In general, the projectiles are propelled by compressed gas generated by a controlled chemical explosion at the base of the weapon. However, some rare instances of guns propel the projectile by means of an electromagnetic field; these are known as railguns. Guns may range from small, handheld weapons up to sizes of 400 millimeters or more in diameter with shells weighing over 900 kilograms.