AIRSOFT GUIDE: Airsoft History
The first airsoft guns were pistols sold in Japan in the early 1980s. The name "Soft-Air" referred to the green gas used as a propellant. Originally designed for target shooting, their bullets could also hit humans without injury and thus became popular for casual war-games. Airsoft guns spread to the UK in the late 1980s and early 1990s with a company called LS. The guns were sold in pieces and had to be assembled before they were capable of firing pellets. Airsoft equipment was designed to closely emulate real guns. Since the mid-1980s, airsoft guns have been adapted with a purely recreational application in mind, and the sport is enjoyed by all ages. Airsoft replicas are produced globally, with the majority being manufactured in Asia. Many law enforcement agencies in the US use Airsoft for force-on-force training drills.
Now that you know a little backround you should know the 3 types of airsoft it will help you figure out the type you want and make it easier when you buy it at a store.
Spring Airsoft
First, spring-powered Airsoft gun, the perfect entry level choice. Spring-cocking guns are true to their name in that you cock the spring first, and then fire. Cock spring, fire, cock, fire, cock, fire, etc. These guns are usually magazine fed and semi-automatic, but they must be hand-cocked after every shot. This system is very cost-effective, and the guns are surprisingly sturdy. Every Airsofter, in his lifetime, has owned at least one spring-powered gun, either a pistol or a rifle. Due to it's relatively cheap price-range, this is usually the gun of choice for the person just starting to play airsoft. A spring-powered handgun can be purchased for as little as $20.Gas Airsoft
Another popular type of an Airsoft gun is the gas-powered. While there are several types of gas-powered airsoft guns, the most popular are the Gas-Blowback guns (GBBs). The GBB allows a realistic, semi-automatic firing of the gun by employing either an on-board, or article-stored gas storage system. Basically, the same compressed air that propels the BB out of the bore is harnessed to cycle the slide back (hence: blowback). This creates the realistic "recoil" by cycling the slide/upper receiver back-and-forth while firing the gun. This system gives the hand-held gun the capability to empty a magazine as fast as you can pull the trigger, and just as easily reload the gun by inserting a fresh magazine. Needless to say, this feature holds tremendous appeal for the "simulationist".Electric Airsoft
Lastly are the Automatic Electric Gun. The creation of the AEG is partly responsible for Airsoft's "boom" during the late 1990s. Basically, an AEG is powered by an on-board battery (similar to hobby R/C Cars), which operates a motor that turns gears inside the gun to compress and release a piston, which in turn creates the blast of air needed to propel the 6mm BB through the barrel of the gun. This system allows the gun to efficiently generate the power needed to support the fully-automatic features of most AEGs and the result is a realistic Rate-Of-Fire (ROF) of anywhere from 600 - 900 Rounds-Per-Minute (RPM), once again mimicking the capabilities of real steel firearms. This is the airsoft gun of choice for most skirmish veterans.