Airsoft is a sport much like Paintball in which players simulate armed combat with authentic military style weapons and tactics. Unlike Paintball which uses paint-balls as projectiles, Airsoft uses 6mm plastic BBs. Furthermore, the 'weapons' used in Airsoft are generally exact replicas of varous real-world military weapons such as the M16, H&K MP5 and so forth.

Airsoft weapons tend to come in three types:

Spring Powered

These weapons fire a BB using a simple spring that has to be cocked by hand. Most spring weapons are for indoor playing as they have limited range and cycle rates (because they must be hand operated).

GAS

These weapons fire BBs using a compressed gas. Once the gas presure drops, more must be added before firing can resume. Typically this is for pistol type weapons and the gas is housed in the gun's clip along with the BBs.

Airsoft Electric Guns (AEG)

These weapons are powered by batteries. Generally the a motor cycles an internal spring and piston chamber which launches the BB projectile with air. These are by far the most commonly used Airsoft weapons. Most AEGs are rifles.

Airsoft BBs tend to fire at about 230 to 500fps. Most "stock" AEGs fire at the low end, but upgrades to the internal components can increase the muzzle velocity. Because the BBs are very light (typically .2 or .25 grams) they have very little kinetic energy on impact compared to a paintball ball. This makes the sport arguably safer than Paintball although protective gear, especially for the eyes, is essential to safe play.

Airsoft has its origins in Asia and is very popular there. However there is a growing number of players in the west. Due to the extremely realistic look of the Airsoft guns, combined with lobbying efforts from U.S. BB gun manfacturers, some states and local regulations may prohibit the ownership or use of Airsoft guns. Federal laws require all Airsoft gun barrels to be painted blaze orange.